Comefri TZAF FF series Manual

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Air Conditioning Division
OPERATING AND MAINTENANCE INSTRUCTIONS OF RADIAL FANS
TZAF FF – VTZ – NTHZ - THLZ FF – MAZ – MHZ – TLZ – TLI – TZAF -
THLZ* - HLZ*- TLE – THLE – KHLE
AND PLENUM FANS
NPL – NPL ALU – NPA – NPA ALU – TE – PEAF*– NPE*
(This manual includes the fan and plenum fan arrangement according to
standard EN 14986 to comply with “ATEX” Directive 94/9/EC)
* THLZ sizes over 450, HLZ, PEAF, NPE series currently not in production but available for spare parts in compliance with this manual.
1 FOREWORD
All Comefri fans and plenum fans are manufactured according to our Quality Assurance
System, in compliance with BS EN ISO 9001; since 1987 our Quality System is certified
by BSI (certificate n° FM 01403). Moreover all fans and plenum fans equipped with motor
are tested accurately before leaving the factory.
Comefri fans and plenum fans are placed on the market in conformity with the
requirements of “ErP” Directive 2009/125/EC and its relevant Regulation N° 327/2011
implementing the Directive in regard with the different product characteristics in terms of
manufacturing and supplying (see par.8);
they are of the state of the art design and comply with the requirements for health and
safety of the Machinery Directive 2006/42/EC.
Comefri defines:
Machine
All fans and plenum fans equipped with connected motor and drive, provided with all the
protections necessary to meet the requirements of the Machinery Directive 2006/42/EC.
Partly Completed Machinery
All other fans and plenum fans which are not included in the previous definition.
This Operating &Maintenance manual (which can be downloaded on www.comefri.com):
- describes the applications for the fans and plenum fans according to the national Stan-
dards, Regulations and Directives, which must be closely observed to avoid possible
damage caused by incorrect installation or mishandling;
- contains notes for health and safety;
- warns of danger which can even occur with correct applications;
- must be read and observed by all personnel. These indications are not the only safety
procedure: any operations made on moving and/or electrical parts, such as installation
and maintenance, require special attention guaranteed only by skilled staff familiar with
safety rules. Besides observance of these instructions, local laws must also be
respected.
- must be accompanied by the relative technical catalogue of the individual product which
must be consulted for all specific information not included in this manual.
The warranty is valid for one year from the delivery date unless otherwise agreed prior to
placing the order. The warranty is only applicable to manufacturing defects, which must
be immediately reported to the manufacturer. A precondition of the warranty is the
observance of the operating instructions. Damage which can be traced back to improper
installation procedures, to the use of damaged fan or plenum fans or unauthorized
alterations to it, such as repairs, are not covered by the Comefri warranty and Comefri is
not liable for resulting damage and costs.
2 TECHNICAL DESCRIPTION
2.1 Fan description
The Comefri fan series TZAF FF, VTZ, NTHZ, THLZ FF, MAZ, MHZ, TLZ, TLI, TZAF,
THLZ, HLZ, TLE, THLE, KHLE
(i)
are centrifugal fans where the air flows axially into the
wheel and is discharged radially in the volute. The performances allow medium and low
air deliveries and medium and high pressures. See the technical documentation in the
relative technical catalogue for the performance of the specific fan. The impellers of our
centrifugal fans can be fitted with forward-curved blades, backward-curved blades or
airfoil backward-curved blades.
The MAZ and MHZ series have more solid features than the TZAF FF and NTHZ series
which makes them specific for heavy-duty air conditioning and industrial applications
where reliability, solidity and easy maintenance play a vital role.
(i) The KHLE series is a “kompakt” version of THLE series with the casing sideplates of rectangular
shape, available in settings 4 or 5, with the same performances of THLE.
The features of each fan series are specified in the technical catalogue that must be
consulted to identify the suitability of the fan for the fluid treated by the system.
Comefri centrifugal fans, with double or single inlet, can be completed with a wide range
of accessories, according to application and installation requirements. The range of
accessories is also completed by protection fittings, in conformity with UNI EN ISO
13857, available on demand. Comefri declines all liability for damage to persons or
objects caused by absence of safety devices or by the use of devices not provided by
Comefri.
Particular attention must be paid in case of direct contact with rotating parts. If this is the
case, the use of specific and adequate personal protective measures (PPE) is essential.
2.2 Plenum Fan impeller description
The Comefri plenum fan series have centrifugal impeller where the air flows axially into
the wheel and is discharged radially outward.
NPL, NPL ALU , TE, NPE plenum fan series have backward-curved blades while the NPA,
NPA ALU , PEAF plenum fan series have airfoil backward-curved bladed impellers. The
performances allow medium and low air deliveries and medium and high pressures. See
the technical documentation in the relative technical catalogue for the performance of the
specific plenum fan.
The features of each plenum fan series are specified in the technical catalogue that must

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be consulted to identify the suitability of the plenum fan for the fluid treated by the
system.
The TE impeller is manufactured in glass reinforced polyamide.
The NPL
ALU and NPA ALU impellers are manufactured in aluminium. The lower weight means less
load on the bearings (longer bearing-life), lower extra-load added on the structures concerned by
installation, also contributing to a reduction on self-induced vibrations. The aluminium alloy used
has excellent resistance to corrosion and is non-toxic, non-magnetic and easy to clean.
Comefri impellers for plenum can be provided as a kit consisting of impeller and inlet-
cone or according to the settings summarized in the Appendix.
Standard setting provided by Comefri is setting 4 which must be installed with horizontal shaft.
Comefri impellers can be completed with a wide range of accessories, according to application
and installation requirements. The range of accessories is also completed by protection fittings
for the inlet-cone and for settings 4 in conformity with UNI EN ISO 13857, available on demand.
Comefri declines all liability for any damage to persons or objects caused by absence of safety
devices or by the use of devices not provided by Comefri. Particular attention must be paid
in case of direct contact with rotating parts: plenum fans do not meet the provisions of the CE
labelling (e.g. they have an impeller without guards). The plenum fan must nevertheless be
installed in accordance with CE requirements.
Plenum fans in ATEX execution provided by factory with all safety devices meet the CE
labelling.
Particular attention must be paid in case of direct contact with rotating parts. If this is the
case, the use of specific and adequate personal protective measures (PPE) is essential.
2.3 Technical data
The technical data and the permissible limits are clearly listed on the fan and plenum fan
label. They can be taken from the appropriate technical catalogue. It is absolutely
forbidden to exceed the machine limits.
For some fans, a part of the catalogue curve is drawn as a dashed line to warn that the
use of the fan in these conditions could generate instability and vibrations due to the
presence of inlet obstructions (like pulley, etc). (For spark-proof execution, see par. 4.5).
For particular executions not foreseen in the catalogue, please contact Comefri.
Noise has been measured according to ISO, DIN, UNI and ANSI-AMCA standards, by means of
a frequency analyzer in real time.
See the appropriate technical catalogue for sound power levels, determined according to
standards DIN 45635 Part38 / ISO 5136 / ANSI-AMCA 330 for in-duct method and according to
ANSI-AMCA 300 for reverberant room method. Values detected by the final user can be
different from those detected during testing since they are affected by specific installation and
environmental and structural factors near the fan or plenum fan and system.
2.4 Applications
The fans and plenum fans are intended to move dust-free air or slightly dusty air. They are not
suitable for aggressive gases, vapours or dusty air. Improper use may cause damage to the
bearings, corrosion, unbalancing of the impeller and vibrations.
The features of each product series are specified in the technical catalogue that must be
consulted to identify the suitability of the fan or plenum fan for the fluid treated by the
system.
Permissible operational temperature range for all fans: -20 °C to +60 °C.
Permissible operational temperature range for impellers of plenum fans (except TE) : -20 °C
to +85 °C; operational temperature range for TE impellers : -20 °C to +60 °C.
For temperatures outside of this range, kindly contact us in order to define the most appropriate
execution.
The maximum ambient temperature of the standard motor is + 40°C.
Consequently plenum fan wheels in all settings where motor is in the flow of the conveyed fluid,
due to temperature limit of motor, operational temperature range is from –20°C to +40°C
according to the motor model and brand.
2.5 Fans and Plenum Fans with spark-proof execution according to ATEX
94/9/EC
The special TZAF FF Atex, VTZ Atex, NTHZ Atex, THLZ FF Atex, MAZ Atex, MHZ Atex, TLZ
Atex, TLI Atex, TZAF Atex, THLZ Atex, HLZ Atex, TLE Atex, THLE Atex, KHLE Atex, NPL Atex,
NPA Atex, TE (in steel ) Atex executions are available for spark-proof applications according to
the ATEX Directive 94/9/EC Group II Category 3G.
TZAF FF Atex, NTHZ Atex, MAZ Atex, MHZ Atex, NPL Atex and NPA Atex are Atex certified to
be used in Group II Category 2G.
THLZ FF and TE series with standard polyamide impellers cannot be in Atex execution; they
can be in Atex execution ONLY with special steel impellers (see par. 2.5.3.1).
Plenum fan series NPL ALU and NPA ALU which are with aluminium wheel cannot be in Atex
execution (see par. 2.5.3.1).
2.5.1 Applications
Fan and plenum fan operating in areas with combustible gases, vapors, mist, dust and fumes or
with a possible danger of explosion must adhere to explosion-proof guidelines. From July 1,
2003 it is necessary for fans and plenum fans intended for use in potentially explosive
atmospheres to comply with the ATEX Directive 94/9/EC.
The ATEX Directive identifies two groups of fan and plenum fan equipment.
Group I: fan and plenum fan equipment intended for use in mining applications (Out of Comefri
production)
Group II: intended for all other situations.
Fans and plenum fans in Group II are divided into three categories, depending on whether
explosion-proof safety has to be assured only under normal operation (Category 3) or also
when malfunctioning or faults occur (Categories 2 and 1).

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Fans and plenum fans classification:
GROUP II *
Category 1
Equipment designed to be capable of functioning in conformity with
the operational parameters established by the manufacturer and
ensuring a very high level of protection.
Equipment in this category is intended for use in areas in which
explosive atmospheres caused by mixtures of air and gases, vapours
or mists or by air/dusts mixtures are present continuously, for long
periods or frequently.
GROUP II Category 2
Equipment designed to be capable of functioning in conformity with
the operational parameters established by the manufacturer and
ensuring a high level of protection.
Equipment in this category is intended for use in areas in which
explosive atmospheres caused by mixtures of air and gases, vapours
or mists or by air/dusts mixtures are likely to occur. The means of
protection relating to equipment in this category shall ensure the
required level of protection, even in the event of frequently occurring
disturbances or equipment faults which normally have to be taken
into account.
GROUP II Category 3
Equipment designed to be capable of functioning in conformity with
the operational parameters established by the manufacturer and
ensuring a normal level of protection.
Equipment in this category is intended for use in areas in which
explosive atmospheres caused by mixtures of air and gases, vapours
or mists or by air/dusts mixtures are unlikely to occur or, if they do
occur, are likely to do so only infrequently and for a short period only.
* Group II, Category 1 (1G, 1D) – fans and plenum fans out of Comefri production.
This fan and plenum fan classification is due to the application of fans and plenum fans in areas
of different explosion danger, where there is a different risk of flammable material being
released to the atmosphere. The areas are classified in Zones: 0, 20, 1, 21, 2, 22.
Codes without prefix “2” refer to an atmosphere containing gas, vapor and mist. Codes with
prefix “2” refer to air containing gas, vapor and also dust. Codes 0, 1 and 2 describe the
likelihood of flammable material being released into the air in explosive concentrations. Zone 0
is the highest risk zone where an explosive atmosphere is expected to exist continuously or for
very long periods of time. Zone 1 is an area where an explosive atmosphere is expected to exist
only for short periods of time. Zone 2 is an area where an explosive concentration of flammable
material is not expected and should it be released it will only exist for a very short period of time.
Pay attention that the presence of dust increases ignition risks and needs further means of
protection (see the following). Please note that Comefri TZAF FF Atex, VTZ Atex, NTHZ Atex,
THLZ FF Atex, MAZ Atex, MHZ Atex, TLZ Atex, TLI Atex, TZAF Atex, THLZ Atex, HLZ Atex,
TLE Atex, THLE Atex, KHLE Atex fans and NPL Atex, NPA Atex, TE (in steel ) Atex plenum
fans are intended to move dust-free air or slightly dusty air.
Zone Explosive
Atmosphere
Dangerous
concentration
Potential spark source must be
avoided
0** Gas, vapour, mist
(G)
Constant or for a
long time
Even where few shutdowns are
expected
20 ** Dust (D) Constant or for a
long time
Even where few shutdowns are
expected
1 Gas, vapour, mist
(G)
Likely to occur More frequent shutdowns are
expected
21 ** Dust (D) Likely to occur More frequent shutdowns are
expected
2 Gas, vapour, mist
(G)
Rarely or for short
time
In normal operation
22 ** Dust (D) Rarely or for short
time
In normal operation
** Out of TZAF FF Atex, VTZ Atex, NTHZ Atex, THLZ FF Atex, MAZ Atex, MHZ Atex, TLZ Atex,
TLI Atex, TZAF Atex, THLZ Atex, HLZ Atex, TLE Atex, THLE Atex, KHLE Atex, NPL Atex, NPA
Atex, TE (in steel ) Atex range of application.
As a consequence, the allowed use of the different category fans and plenum fans depending
on the different zones is:
Fan Category Designed for zone Also applicable in zones
1 G *** 0 1, 2
1 D *** 20 21 , 22
2 G **** 1 2
2 D ***** 21 22
3 G 2 -
3 D ***** 22 -
*** Group II, Category 1 fans and plenum fans are out of Comefri production.
**** Only for TZAF FF Atex, NTHZ Atex, MAZ Atex, MHZ Atex fan series and NPL Atex, NPA
Atex plenum fan series.
***** The use of the fan and plenum fans in dusty environments is out of the range of application
of TZAF FF Atex, VTZ Atex, NTHZ Atex, THLZ FF Atex, MAZ Atex, MHZ Atex, TLZ Atex, TLI
Atex, TZAF Atex, THLZ Atex, HLZ Atex, TLE Atex, THLE Atex, KHLE Atex, NPL Atex, NPA
Atex, TE (in steel ) Atex.
Comefri TZAF FF Atex, VTZ Atex, NTHZ Atex, THLZ FF Atex, MAZ Atex, MHZ Atex, TLZ Atex,
TLI Atex, TZAF Atex, THLZ Atex, HLZ Atex, TLE Atex, THLE Atex, KHLE Atex fans and NPL
Atex, NPA Atex, TE (in steel ) Atex plenum fans in no-sparking execution are suitable for
atmospheres with a maximum 21 vol% oxygen content, absolute pressure from 0.8 bar to 1.1
bar and gas explosion Groups IIA and IIB.
Correspondence of the fan category to the inside/outside hazardous zone.
The explosion risk occurs either due to the explosive gas moved by the fan or due to the
presence of explosive gas in the areas where the fan is placed. The risk analysis must therefore
consider both outside and inside the fan.
TZAF FF Atex, VTZ Atex, NTHZ Atex, THLZ FF Atex, MAZ Atex, MHZ Atex, TLZ Atex, TLI Atex,

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TZAF Atex, THLZ Atex, HLZ Atex, TLE Atex, THLE Atex, KHLE Atex fans can be installed
(according to DIN EN ISO 5801) in mode A (without inlet and outlet duct) or mode B (without
inlet duct and with outlet duct). Therefore they have the same explosive atmosphere and require
the same equipment category inside and outside.
TLE Atex, THLE Atex, KHLE Atex fans must have the same requirements as above when
installed in mode A and B. Installation in mode C (with inlet duct and without outlet duct) has the
same requirements as needed for modes A and B. TLE Atex, THLE Atex, and KHLE Atex fans
can also be installed in mode D (with inlet and outlet ducts). In this case, provided the fan has
been requested in leak proof execution, the fan has to be designed for different category inside
and outside as indicated in the table below and according to the following: if the fan is placed in
open field or in a well ventilated room and considering that the leak proof execution is not
absolutely gas tight, then there is never more than one category of difference between the
highest category and the lowest category inside and outside.
This means for instance that an internal hazard 2 G automatically requires that the outside of
the fan is considered hazard Category 3 G.
Category inside the fan enclosure
Non-explosive
atmosphere Category 3 gas Category 2 gas
Category outside the
fan enclosure
Non-
explosive
atmosphere
No requirements
inside: cat. 3
outside: no
requirements
inside: cat. 2
outside: cat. 3
Category 3
gas
inside: no
requirements
outside: cat. 3
inside: cat. 3
outside: cat. 3
Inside: cat. 2
outside: cat. 3
Category 2
gas
inside: cat. 3
outside: cat. 2
inside: cat. 3
outside: cat. 2
inside: cat. 2
outside: cat. 2
If the fan is placed in a closed unventilated room, the category selected for the more restrictive
hazardous zone must be applied for both the outside and inside of the fan casing. This means
for instance that an internal hazard 2 G will require that the outside of the fan is considered 2 G
hazard Category.
2.5.2 Temperature
The user must choose the appropriate temperature class consistent with the minimum ignition
temperature of the gas, mist or dust (see table below). The temperature class indicates the
maximum surface temperature reached by the fan and plenum fan during operation in which the
temperature of the inlet fluid is inside the permissible Atex temperature range (standard
permissible Atex temperature range is from –20 to +60 °C).
Generally the maximum temperature rise will occur at minimum flow and maximum density. If
the system designer is unable to guarantee the safe minimum or maximum air flow, for
Category 2 fans, temperature monitoring devices have to be installed, which in case of a
dangerous temperature rise will automatically activate emergency functions, e.g. fan shut down
or bypassing, e.g. with dampers.
In case of presence of lightly dusty air, the ignition risk assessment shall consider the
temperature raising of dust or other material trapped between two moving parts or a moving
part and a fixed part, especially if material remains in contact with the same moving part for a
long period.
NOTE: the maximum temperature indicated on the fan and plenum fans label refers to operating
conditions without dust.
The user must evaluate the relation between the maximum surface temperature and the
minimum ignition temperature of the dust according to operating conditions.
For dust problems, also see standard EN 1127-1 which has indications concerning protective
measures to be taken.
Temperature class Maximum surface temperature [°C]
T1 ****** 450
T2 300
T3 200
T4 135
T5 100
T6 85
****** Generally for mining applications.
The temperature class is indicated in the fan and plenum fans label (see par. 2.5.5).
The temperature class for double inlet fan series in Group II Category 3G (TZAF FF Atex, VTZ
Atex, NTHZ Atex, THLZ FF Atex, MAZ Atex, MHZ Atex, TLZ Atex, TLI Atex, TZAF Atex, THLZ
Atex, HLZ Atex) is T4.
For double inlet fan series in Group II Category 2G see par. 2.5.3.3.
The temperature class for single inlet fan series (TLE Atex, THLE Atex) and plenum fan series
in setting 11 (NPL Atex arr.11, NPA Atex arr.11) is T3.
NOTE for settings 4 and 5. For single inlet fan series TLE Atex, THLE Atex, KHLE Atex
achieved in settings 4 and 5 and for plenum fan series NPL Atex, NPA Atex, TE (in steel) Atex
achieved in settings 4 and 5 the temperature class corresponds with the temperature class of
the installed motor.
The difference between double and inlet fans is mainly due to the bearing, which is the most
critical element concerning heating.
NOTE: for plenum fans in settings with impeller installed on the motor shaft, as a rule the
temperature class is set equal to the motor temperature class and is quoted also on the plenum
fan label.
2.5.3 Spark protection measures and mechanical design criteria
2.5.3.1 CRITERIA FOR BOTH CATEGORY 2 AND 3 - Gas
-- General
Comefri fans and plenum fans (casings, supporting structures, guards, protective enclosure and
other external parts) are of a rigid design. Deformation resulting from a single impact at the

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most vulnerable point is so small that the moving parts do not come into contact with the casing
or the protective enclosure. For this reason the impact test is considered unnecessary.
-- Casing
When the fan is driven by a motor of more than 11kW, then the casing is continuously welded.
For MAZ Atex and MHZ Atex fans, the casing is continuously welded as per standard. The fan
is equipped with an inspection door. It is held in position by bolts and sealed.
-- Impellers
Comefri TZAF FF Atex, VTZ Atex, NTHZ Atex, THLZ FF Atex, MAZ Atex, MHZ Atex, TLZ Atex,
TLI Atex, TZAF Atex, THLZ Atex, HLZ Atex, TLE Atex, THLE Atex, KHLE Atex, NPL Atex, NPA
Atex, TE (in steel ) Atex impellers are of a rigid design.
For Atex execution, the impeller of THLZ and THLZ FF from 180 to 450 and the TE series must
be manufactured in steel, NOT in glass reinforced polyamide as in the standard execution.
NPL ALU e NPA ALU cannot be used in Atex applications.
The impeller shaft must be installed in a horizontal position.
-- Materials for rotating and stationary parts
In view of misuse, due to rare or even very rare malfunctioning, potential areas of contact
between the rotating elements and fixed components have been manufactured from materials in
which the risk of ignition through friction and friction-impact sparks is minimized as EN 14986
par. 4.8.2.
The material pairings chosen for Comefri fans and plenum fans for the stationary rubbing part
and the rotating rubbing part are as in the table below. The material of the rotating part assures
the mechanical stress performance.
Stationary part Moving part
Copper Steel, stainless steel or cast-iron
This material combination is accomplished making the whole component from that material or
using tip extensions and linings of that material.
Tip extensions and linings have a minimum thickness as given in the table below in order to
withstand impact or abrasion for an appreciable time:
Motor power [kW] Thickness of copper tips [mm]
=< 11 2
> 11 to 90 3
> 90 to 250 4
> 250 5
The tips are securely attached to the base material by welding.
Potential areas of contact between the rotating elements and fixed components and relative
provisions adopted to satisfy requirement of EN 14986 par. 4.8.2:
INLET-CONE and SHROUD Inlet-cones are provided in the proximity of the wheel with an
extension made of copper or are completely made of copper
FOREFINGER
®
and SHROUD Forefinger
®
is manufactured in copper for Atex applications
SINGLE INLET WHEEL BACKPLATE – CASING SIDEPLATE There is a risk of contact
between wheel backplate and/or hub and the casing sideplate and therefore a copper plate is
installed internally of the sideplate.
TRANSMISSION GUARD There is a risk of contact between guard and pulleys and motor / fan
shafts and therefore a copper plate is installed in the internal side of the guard in front of the
pulleys.
These protections are fixed with brass screws.
PROTECTIVE ENCLOSURE FOR PLENUM FANS For plenum fans it is necessary a
protective enclosure around the wheel (see in the following). A potential explosion risk can
come from an accidental contact between rotating parts as wheel back-plate and/or wheel hub
(depending on which one is the most protuberant to enclosure), the passing motor shaft and
closest stationary parts as the enclosure wall, the outward frame supporting the enclosure if the
wheel diameter is up to it, the motor-support wall facing the wheel or the clearance hole in the
enclosure for the passing motor shaft.
To satisfy Atex requirements a copper plate is fixed on the guard in front of the wheel or for
small sizes the guard wall in front of the wheel is completely manufactured in copper.
All screws used for fixing these copper anti-spark protections are of brass.
Paints do not contain more than 10 % aluminium per unit mass and do not contain iron oxides,
which can cause aluminothermic sparks.
NOTE: cooling wheel is a rotating part that shall satisfy Atex requirement of EN 14986 par.
4.8.2. Because in Atex application max temperature of input air is +60 °C, cooling wheel is not
necessary and therefore it must not be used.
-- Vibrations
The impeller or the complete rotating assembly is balanced according to ISO 1940-1 and ISO
14694, grade 2.5. In case of belt transmission the pulleys are also balanced.
The completed fan and plenum fan meet the vibration levels recommended in ISO 10816 and
ISO 14694.
2.5.3.2 FURTHER CRITERIA FOR CATEGORY 3 – Gas
-- Deposits inside the fan
TZAF FF Atex, VTZ Atex, NTHZ Atex, THLZ FF Atex, MAZ Atex, MHZ Atex, TLZ Atex, TLI Atex,
TZAF Atex, THLZ Atex, HLZ Atex, TLE Atex, THLE Atex, KHLE Atex fan series and NPL Atex,
NPA Atex, TE (in steel ) Atex plenum fan series treated in this manual are intended to move
dust-free air or slightly dusty air, as already mentioned. Many types of dust, mist and droplets
may be in suspension in the air flow. Even small quantities of impurities may in time form layers
of combustible or non-combustible material within the fan and adhere to rotating parts. Even
normal ambient air may contain sufficient airborne particles to form layers, which may increase

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the risk of ignition. For no-spark execution, TZAF FF Atex, VTZ Atex, NTHZ Atex, THLZ FF
Atex, MAZ Atex, MHZ Atex, TLZ Atex, TLI Atex, TZAF Atex, THLZ Atex, HLZ Atex, TLE Atex,
THLE Atex, KHLE Atex fans are provided with an inspection door, so that inspection and
cleaning operations can be easily carried out.
-- Clearance between rotating parts and the stationary parts
The clearance between rotating elements and the fan casing / stationary parts is the most im-
portant safety feature of ignition minimizing fans. The minimum clearances between rotating
components such as the impeller and fixed components e.g. the fan casing are at least 1 % of
the relevant contact diameters of the finished component, but are not less than 2 mm in the axi-
al or radial directions nor need to be more than 20 mm.
This clearance may be reduced to 10 % of the shaft diameter (minimum 2 mm and maximum 13
mm). Shaft seals are not subject to this provision.
Comefri provisions satisfy this requirement for all potential areas of contact listed in the previous
paragraph “Materials for rotating and stationary parts”.
Clearance between inlet-cone and shroud is indicated in the Appendix for each Comefri fan and
plenum fan series.
NOTE: the clearance may change with rotation, temperature, and due to vibrations and belt
drive tension. For this reason the installer / user must assure the correct belt tension (see par.
6.5) and check the final clearance after tensioning (see par. 4.5).
Copper plates in front of rotating parts (pulleys, hubs, back-plate, etc.) have an outer dimension
at least from 5 to 10 mm greater than rotating part dimension; clearance between the motor or
fan shaft and the edge of the passage hole is designed as indicated here above.
In case of plenum fans provided as loose components (i.e. wheel and inlet-cone) it is duty of the
installer / user to adjust the centring between inlet-cone and shroud in order to achieve a
constant clearance all around the circumference that must comply with the value indicated in
the Appendix.
-- Bearings
Bearings are designed for an L
10
life of at least 20000 hours in accordance with ISO 281. This
requirement is guaranteed only if the diameter of the pulley respects a minimal value according
to our fan-selection program Aeolus (see par. 4.3)
-- Power transmission systems
V-belts must be electrostatically conductive and must withstand short-term exposure to flames
(see par. “Fire resistance” here following). They must be declared by manufacturer to be
compliant with Atex requirements.
-- Couplings
Couplings are arranged so that the rotating part that is exposed to the potentially explosive
atmosphere does not exceed the maximum surface temperature of the fan. Couplings shall be
in compliance with Atex Directive.
-- Impeller - shaft attachment
For motor powers in excess of 15 kW a positive locking is arranged using seeger rings on the
shaft for single and double inlet fans; the use of the seeger rings at the fan shaft restricts the
maximal rotational speed: the maximal permissible rotational speed is indicated in the label. For
single inlet wheels directly coupled to the motor, positive locking is performed with a locking
screw and washer at the tapped shaft.
NOTE: special execution with a taper-bushed connection of the impeller to the shaft is used for
fans with motor power not exceeding 15 kW.
For plenum fans in setting 4 impeller hub is positive locked to motor shaft between the shaft
shoulder, with eventually a washer in front of the shoulder (ex. in case of hub in aluminum), and
a locking screw and washer at the tapped shaft end.
In case of plenum fans provided as loose components, i.e. wheel and inlet-cone, a positive
locking of impeller hub is duty of the customer.
-- Corrosion
Corrosion of fan and plenum fan components can in several ways lead to an ignition risk. The
materials used for Comefri fans and plenum fans are therefore corrosion protected by paint or
zinc-coating or manufactured in stainless steel.
The possibility of the fan and plenum fan being exposed to other corrosive chemical
constituents of the gas shall be identified by the customer and communicated to Comefri in
order to get approval or indications for special settings to be carried out.
-- Fire resistance
The materials used for the impeller, fan casing of Comefri TZAF FF Atex, VTZ Atex, NTHZ Atex,
THLZ FF Atex, MAZ Atex, MHZ Atex, TLZ Atex, TLI Atex, TZAF Atex, THLZ Atex, HLZ Atex,
TLE Atex, THLE Atex, KHLE Atex fan series and for the impeller, structure of Comefri NPL
Atex, NPA Atex, TE (in steel ) Atex plenum fan series withstand short-term exposure to flames.
(The requirement is met if the components are only partly destroyed without the onset of a self-
sustaining combustion when exposed to a (propane) Bunsen burner flame approximately 150
mm long for 30 seconds without additional air supply).
-- Protection against foreign particles
As required by Standard EN 14986, the fan and plenum fan shall be protected against the entry
of foreign particles according to grade IP20 of EN 60529.
Fans:
Comefri fans are provided with proper inlet and outlet protective guards according to grade IP20
compliant with the Standard requirement.
Plenum fans:
Comefri standard Atex execution provides plenum fans in setting 4 equipped with the proper
protection guard at the inlet and the protective enclosure at the outlet according to grade IP20
compliant with the Standard requirement. The guard of the protection enclosure is fixed at the
front panel of the structure and at an auxiliary frame provided between motor and wheel (see
sketch in the appendix).
These guards and protective enclosures shall not be tampered, nor substituted with others of
different type, causing the decay of the Comefri certification for Atex execution.

Operating and Maintenance Manual - Air Conditioning Division
Make sure that the fan is always accompanied
by this manual.
7/42
As exception fan or plenum fan can be supplied without protections provided both the following
conditions are respected:
- the customer has produced a written declaration where he states that upon analysis the kind
of installation has proved to be itself a guarantee of IP20 protection and
- the customer requires by writing in the commercial order not to supply the protections.
As warned in the Standard EN 14986, the presence of inlet and/or outlet duct is not itself a
guarantee of IP 20 protection, but the risk of entry of foreign particles is to be analyzed anyway.
2.5.3.3 FURTHER CRITERIA FOR CATEGORY 2 – Gas
The TZAF FF Atex, NTHZ Atex, MAZ Atex, MHZ Atex fan and NPL Atex, NPA Atex plenum fan
series are the only ones among the fan series in the present catalogue that are certified to be
used also in Atex Group II Category 2G. All characteristics explained for Category 3 are valid
also for Category 2 with the further additional and/or predominant Atex Category 2 requirements
detailed here following.
TZAF FF Atex, NTHZ Atex
-- Bearings
The L
10
minimum life shall not be less than 40000 hours. This requirement is guaranteed only if
the diameter of the pulley respects a minimal value according to our fan-selection program
Aeolus (see par. 4.3)
-- Impeller - shaft attachment
Fan series TZAF FF Atex.and NTHZ Atex
For motor powers in excess of 5.5 kW a positive locking is achieved for the fixing of hub on the
shaft with the use of the key and relative safe grub screw and arranging a couple of seeger
rings or stop bushings on the shaft between the hub for single and double inlet fans. For single
inlet fans directly coupled to the motor, positive locking is performed with a locking screw and
washer at the tapped shaft end. The use of the seeger rings on the fan shaft restricts the
maximal permissible rotational speed of the standard catalogue limits to the rotational speed
limits reported in the following tables.
For motor powers less than 5.5 kW the fixing of the hub on the shaft can be achieved also the
use of the key and relative safe grub screw
Rotational speed limit is indicated in the fan label.
Fan Model
Arr.
Max RPM
Arr.
Max RPM
Arr.
Max RPM
Arr.
Max RPM
Stop
bushing
Seeger
ring
Stop
bushing
Seeger
ring
Stop
bushing
Seeger
ring
Stop
bushing
Seeger
ring
TZAF 315 FF
R 3350 2730 T1 4000 3000 - - - T2 4000 3700
TZAF 355 FF
R
3000 3000 T1
3650 3200 -
- - T2
4000 3770
TZAF 400 FF
R
2700 2700 T1
3200 2750 T2L
3215 3000 T2
3700 3200
TZAF 450 FF
R
2400 2400 T1
2850 2650 T2L
2950 2750 T2
3300 2900
TZAF 500 FF
R
2100 1850 T1
2300 1960 T2L
2500 2210 T2
2820 2400
TZAF 560 FF
R
1950 1820 T1
2200 1870 T2L
2650 2350 T2
2700 2350
TZAF 630 FF
R
1550 1400 T1
1700 1450 T2L
2250 1920 T2
2350 2000
TZAF 710 FF
R
1370 1350 T1
1700 1450 T2L
1850 1800 T2
2100 1850
TZAF 800 FF
- - - T1
1300 1120 T2L
1650 1470 T2
1800 1550
TZAF 900 FF
- - - T1
1300 1200 T2L
1450 1300 T2
1600 1450
TZAF 1000 FF
- - - T1
1050 900 T2L
1250 1120 T2
1400 1270
TZAF 1120 FF
- - - T1
850 770 -
- - T2
1200 1150
TZAF 1250 FF
- - - T1
800 700 -
- - T2
1100 1070
AISI 304 and AISI 304 L EXECUTION
Max RPM limits are the same for execution with stop bushing and with seeger ring
Fan model arr. Max RPM arr.
Max RPM arr. Max RPM arr. Max RPM
TZAF 315 FF R 2730 T1 3000 - - T2 3400
TZAF 355 FF R 2550 T1 3100 - - T2 3400
TZAF 400 FF R 2295 T1 2720 T2L 2735 T2 3145
TZAF 450 FF R 2040 T1 2425 T2L 2510 T2 2805
TZAF 500 FF R 1785 T1 1955 T2L 2125 T2 2400
TZAF 560 FF R 1660 T1 1870 T2L 2255 T2 2295
TZAF 630 FF R 1320 T1 1445 T2L 1915 T2 2000
TZAF 710 FF R 1165 T1 1445 T2L 1575 T2 1785
TZAF 800 FF - - T1 1105 T2L 1405 T2 1530
TZAF 900 FF - - T1 1105 T2L 1235 T2 1360
TZAF 1000 FF - - T1 895 T2L 1065 T2 1190
TZAF 1120 FF - - T1 720 - - T2 1020
TZAF 1250 FF - - T1 680 - - T2 935
AISI 316 and AISI 316 L EXECUTION
Max RPM limits are the same for execution with stop bushing and with seeger ring
Fan model arr. Max RPM arr.
Max RPM arr. Max RPM arr. Max RPM
TZAF 315 FF R 2510 T1 3000 - - T2 3000
TZAF 355 FF R 2250 T1 2740 - - T2 3000
TZAF 400 FF R 2025 T1 2400 T2L 2410 T2 2275
TZAF 450 FF R 1800 T1 2140 T2L 2215 T2 2475
TZAF 500 FF R 1575 T1 1725 T2L 1875 T2 2115
TZAF 560 FF R 1465 T1 1650 T2L 1990 T2 2025
TZAF 630 FF R 1165 T1 1275 T2L 1690 T2 1765
TZAF 710 FF R 1030 T1 1275 T2L 1390 T2 1575
TZAF 800 FF - - T1 975 T2L 1240 T2 1350
TZAF 900 FF - - T1 975 T2L 1090 T2 1200
TZAF 1000 FF - - T1 790 T2L 940 T2 1050
TZAF 1120 FF - - T1 640 - - T2 900
TZAF 1250 FF - - T1 600 - - T2 825

Operating and Maintenance Manual - Air Conditioning Division
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8/42
Duplex EXECUTION
Fan Model
Arr.
Max RPM
Arr.
Max RPM
Arr.
Max RPM
Arr.
Max RPM
Stop
bushing
Seeger
ring
Stop
bushing
Seeger
ring
Stop
bushing
Seeger
ring
Stop
bushing
Seeger
ring
TZAF 315 FF
R 3350 2730 T1 4000 3000 - - - T2 4000 3700
TZAF 355 FF
R
3000 3000 T1
3650 3200 -
- - T2
4000 3770
TZAF 400 FF
R
2700 2700 T1
3200 2750 T2L
3215 3000 T2
3700 3200
TZAF 450 FF
R
2400 2400 T1
2850 2650 T2L
2950 2750 T2
3300 2900
TZAF 500 FF
R
2100 1850 T1
2300 1960 T2L
2500 2210 T2
2820 2400
TZAF 560 FF
R
1950 1820 T1
2200 1870 T2L
2650 2350 T2
2700 2350
TZAF 630 FF
R
1550 1400 T1
1700 1450 T2L
2250 1920 T2
2350 2000
TZAF 710 FF
R
1370 1350 T1
1700 1450 T2L
1850 1800 T2
2100 1850
TZAF 800 FF
- - - T1
1300 1120 T2L
1650 1470 T2
1800 1550
TZAF 900 FF
- - - T1
1300 1200 T2L
1450 1300 T2
1600 1450
TZAF 1000 FF
- - - T1
1050 900 T2L
1250 1120 T2
1400 1270
TZAF 1120 FF
- - - T1
850 770 -
- - T2
1200 1150
TZAF 1250 FF
- - - T1
800 700 -
- - T2
1100 1070
Fan Model
Arr.
Max RPM
Arr.
Max RPM
Arr.
Max RPM
Arr.
Max RPM
Stop
bushing
Seeger
ring
Stop
bushing
Seeger
ring
Stop
bushing
Seeger
ring
Stop
bushing
Seeger
ring
NTHZ 315
R 3550 3150 T1 3700 3150 - - - T2 3900 3650
NTHZ 355
R
3150 3150 T1
3400 3200 -
- - T2
3850 3600
NTHZ 400
R
2800 2380 T1
2950 2400 T2L
3200 2700 T2
3600 2900
NTHZ 450
R
2400 2380 T1
2650 2400 T2L
2950 2700 T2
3230 2750
NTHZ 500
R
2100 1850 T1
2200 1870 T2L
2500 2215 T2
2720 2275
NTHZ 560
R
1950 1790 T1
2050 1800 T2L
2400 2200 T2
2600 2200
NTHZ 630
R
1550 1370 T1
1650 1400 T2L
2100 1800 T2
2275 1850
NTHZ 710
R
1350 1350 T1
1500 1350 T2L
1850 1750 T2
2015 1820
NTHZ 800
- - - T1
1200 1050 T2L
1500 1325 T2
1700 1425
NTHZ 900
- - - T1
1200 1050 T2L
1350 1250 T2
1500 1350
NTHZ 1000
- - - T1
1050 850 T2L
1150 1050 T2
1260 1150
NTHZ 1120
- - - T1
825 750 -
- - T2
1175 1100
NTHZ 1250
- - - T1
765 650 -
- - T2
1050 1000
AISI 304 and AISI 304 L EXECUTION
Max RPM limits are the same for execution with stop bushing and with seeger ring
Fan model arr. Max RPM arr.
Max RPM arr. Max RPM arr. Max RPM
NTHZ 315 R 3020 T1 3145 - - T2 3315
NTHZ 355 R 2680 T1 2890 - - T2 3275
NTHZ 400 R 2380 T1 2400 T2L 2700 T2 2900
NTHZ 450 R 2040 T1 2255 T2L 2510 T2 2750
NTHZ 500 R 1785 T1 1870 T2L 2125 T2 2275
NTHZ 560 R 1660 T1 1745 T2L 2040 T2 2200
NTHZ 630 R 1320 T1 1400 T2L 1785 T2 1850
NTHZ 710 R 1150 T1 1275 T2L 1575 T2 1715
NTHZ 800 - - T1 1020 T2L 1275 T2 1425
NTHZ 900 - - T1 1020 T2L 1150 T2 1275
NTHZ 1000 - - T1 850 T2L 980 T2 1070
NTHZ 1120 - - T1 700 - - T2 1000
NTHZ 1250 - - T1 650 - - T2 895
AISI 316 and AISI 316 L EXECUTION
Max RPM limits are the same for execution with stop bushing and with seeger ring
Fan model arr. Max RPM arr.
Max RPM arr. Max RPM arr. Max RPM
NTHZ 315 R 2665 T1 2775 - - T2 2925
NTHZ 355 R 2365 T1 2550 - - T2 2890
NTHZ 400 R 2100 T1 2215 T2L 2400 T2 2700
NTHZ 450 R 1800 T1 1990 T2L 2215 T2 2425
NTHZ 500 R 1575 T1 1650 T2L 1875 T2 2040
NTHZ 560 R 1465 T1 1540 T2L 1800 T2 1950
NTHZ 630 R 1165 T1 1240 T2L 1575 T2 1705
NTHZ 710 R 1015 T1 1125 T2L 1390 T2 1510
NTHZ 800 - - T1 900 T2L 1125 T2 1275
NTHZ 900 - - T1 900 T2L 1015 T2 1125
NTHZ 1000 - - T1 790 T2L 865 T2 945
NTHZ 1120 - - T1 620 - - T2 880
NTHZ 1250 - - T1 575 - - T2 790
Duplex EXECUTION
Fan Model
Arr.
Max RPM
Arr.
Max RPM
Arr.
Max RPM
Arr.
Max RPM
Stop
bushing
Seeger
ring
Stop
bushing
Seeger
ring
Stop
bushing
Seeger
ring
Stop
bushing
Seeger
ring
NTHZ 315
R 3550 3150 T1 3700 3150 - - - T2 3900 3650
NTHZ 355
R
3150 3150 T1
3400 3200 -
- - T2
3850 3600
NTHZ 400
R
2800 2380 T1
2950 2400 T2L
3200 2700 T2
3600 2900
NTHZ 450
R
2400 2380 T1
2650 2400 T2L
2950 2700 T2
3230 2750
NTHZ 500
R
2100 1850 T1
2200 1870 T2L
2500 2215 T2
2720 2275
NTHZ 560
R
1950 1790 T1
2050 1800 T2L
2400 2200 T2
2600 2200
NTHZ 630
R
1550 1370 T1
1650 1400 T2L
2100 1800 T2
2275 1850
NTHZ 710
R
1350 1350 T1
1500 1350 T2L
1850 1750 T2
2015 1820
NTHZ 800
- - - T1
1200 1050 T2L
1500 1325 T2
1700 1425
NTHZ 900
- - - T1
1200 1050 T2L
1350 1250 T2
1500 1350
NTHZ 1000
- - - T1
1050 850 T2L
1150 1050 T2
1260 1150
NTHZ 1120
- - - T1
825 750 -
- - T2
1175 1100
NTHZ 1250
- - - T1
765 650 -
- - T2
1050 1000
-- Casing
According to TZAF FF Atex and NTHZ Atex Technical Documentation deposited by the Notified
Body, casing of TZAF FF Atex and NTHZ Atex fans are manufactured in galvanized and painted
steel up to size 1000 and in black and painted steel over size 1000 or in AISI 304, in AISI 304L,
in AISI 316, in AISI 316L or in Duplex SS2205.
Casing is continuously welded.
Casing is provided with inspection door.
The standard EN 14986 requires that the inspection door, outlet and inlet joints and the
eventual holes in the casing for the fixing screws shall be sealed. As a consequence the casing
can be considered as gas tight without release (or with reduced release); this could be an aim in
the single inlet fan series, but it is out of application in the double inlet fan series, as for the

Operating and Maintenance Manual - Air Conditioning Division
Make sure that the fan is always accompanied
by this manual.
9/42
TZAF FF Atex, NTHZ Atex object of the Category 2G certification.
The fan shaft must be installed in a horizontal position.
-- Application limits as declared in the Technical Documentation deposited by the Notified Body.
Fans shall operate inside the field covered by the catalogue curves, the use of the fan outside
this field could generate instability and vibrations;
for some fans, a part of the catalogue curve is drawn as a dashed line; this means that the use
of the fan in these conditions could generate instability and vibrations, due to the presence of
inlet obstructions (pulley, etc):
therefore in Atex application the fan must absolutely NOT be used outside catalogue field and in
the zone of dashed-line curves.
TZAF FF Atex and NTHZ Atex:
absolute pressure from 0.8 bar to 1.1 bar;
aerodynamic energy increase of less than 25 kJ/kg;
atmospheres with a maximum 21 vol% oxygen content;
maximal temperature range of conveyed fluid between -20 and +60 °C
(except. from more stringent limits according to the motor model and brand installed);
gas explosion Groups IIA and IIB;
temperature class T3
As already declared for all fans of this handbook: no for conveying fluids containing dust.
MAZ Atex, MHZ Atex
-- Bearings
The L
10
minimum life shall not be less than 40000 hours. This requirement is guaranteed only if
the diameter of the pulley respects a minimal value according to our fan-selection program
Aeolus (see par. 4.3)
-- Impeller - shaft attachment
Fan series MAZ Atex and MHZ Atex.
For motor powers in excess of 5.5 kW a positive locking is achieved for the fixing of hub on the
shaft with the use of the key and relative safe grub screw and arranging a couple of seeger
rings or stop bushings on the shaft between the hub for single and double inlet fans. For single
inlet fans directly coupled to the motor, positive locking is performed with a locking screw and
washer at the tapped shaft end. The use of the seeger rings on the fan shaft restricts the
maximal permissible rotational speed of the standard catalogue limits to the rotational speed
limits reported in the following tables.
For motor powers less than 5.5 kW the fixing of the hub on the shaft can be achieved also with
the use of the key and relative safe grub screw
Rotational speed limit is indicated in the fan label.
Fan Model arr
Max RPM
arr
Max RPM
arr
Max RPM
Stop
bushing
Seeger
ring
Stop
bushing
Seeger
ring
Stop
bushing
Seeger
ring
MAZ 315 T1 4000 3000 - - - T2 4000 3700
MAZ 355 T1 3650 3200 - - - T2 4000 3770
MAZ 400 T1 3200 2750 T2L 3215 3000 T2 3700 3200
MAZ 450 T1 2850 2650 T2L 2950 2750 T2 3300 2900
MAZ 500 T1
2300 1960 T2L
2500 2210 T2 2820 2400
MAZ 560 T1
2200 1870 T2L
2650 2350 T2 2700 2350
MAZ 630 T1 1700 1450 T2L 2250 1920 T2 2350 2000
MAZ 710 T1 1700 1450 T2L 1850 1800 T2 2100 1850
MAZ 800 T1 1300 1120 T2L 1650 1470 T2 1800 1550
MAZ 900 T1
1300 1200 T2L
1450 1300 T2 1600 1450
MAZ 1000 T1
1050 900 T2L
1250 1120 T2 1400 1270
MAZ 1120 T1 850 770 - - - T2 1200 1150
MAZ 1250 T1 800 700 - - - T2 1100 1070

Operating and Maintenance Manual - Air Conditioning Division
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10/42
AISI 304 and AISI 304 L EXECUTION
Max RPM limits are the same for execution with stop bushing and with seeger ring
Fan model arr. Max RPM arr. Max RPM arr. Max RPM
MAZ 315 T1 3400 - - T2 3400
MAZ 355 T1 3100 - - T2 3400
MAZ 400 T1 2720 T2L 2735 T2 3145
MAZ 450 T1 2425 T2L 2510 T2 2805
MAZ 500 T1 1955 T2L 2125 T2 2400
MAZ 560 T1 1870 T2L 2255 T2 2295
MAZ 630 T1 1445 T2L 1915 T2 2000
MAZ 710 T1 1445 T2L 1575 T2 1785
MAZ 800 T1 1105 T2L 1405 T2 1530
MAZ 900 T1 1105 T2L 1235 T2 1360
MAZ 1000 T1 895 T2L 1065 T2 1190
MAZ 1120 T1 720 - - T2 1020
MAZ 1250 T1 680 - - T2 935
AISI 316 and AISI 316 L EXECUTION
Max RPM limits are the same for execution with stop bushing and with seeger ring
Fan model arr. Max RPM arr. Max RPM arr. Max RPM
MAZ 315 T1 3000 - - T2 3000
MAZ 355 T1 2740 - - T2 3000
MAZ 400 T1 2400 T2L 2410 T2 2775
MAZ 450 T1 2140 T2L 2215 T2 2475
MAZ 500 T1 1725 T2L 1875 T2 2115
MAZ 560 T1 1650 T2L 1990 T2 2025
MAZ 630 T1 1275 T2L 1690 T2 1765
MAZ 710 T1 1275 T2L 1390 T2 1575
MAZ 800 T1 975 T2L 1240 T2 1350
MAZ 900 T1 975 T2L 1090 T2 1200
MAZ 1000 T1 790 T2L 940 T2 1050
MAZ 1120 T1 640 - - T2 900
MAZ 1250 T1 600 - - T2 825
Duplex
Fan Model arr
Max RPM
arr
Max RPM
arr
Max RPM
Stop
bushing
Seeger
ring
Stop
bushing
Seeger
ring
Stop
bushing
Seeger
ring
MAZ 315 T1 4000 3000 - - - T2 4000 3770
MAZ 355 T1 3650 3200 - - - T2 4000 3770
MAZ 400 T1
3200 2750 T2L
3215 3000 T2 3700 3200
MAZ 450 T1
2850 2650 T2L
2950 2750 T2 3300 2900
MAZ 500 T1 2300 1960 T2L 2500 2210 T2 2820 2400
MAZ 560 T1 2200 1870 T2L 2650 2350 T2 2700 2350
MAZ 630 T1 1700 1450 T2L 2250 1920 T2 2350 2000
MAZ 710 T1 1700 1450 T2L 1850 1800 T2 2100 1850
MAZ 800 T1
1300 1120 T2L
1650 1470 T2 1800 1550
MAZ 900 T1
1300 1200 T2L
1450 1300 T2 1600 1450
MAZ 1000 T1 1050 900 T2L 1250 1120 T2 1400 1270
MAZ 1120 T1 850 770 - - - T2 1200 1150
MAZ 1250 T1 800 700 - - - T2 1100 1070
Fan Model arr
Max RPM
arr
Max RPM
arr
Max RPM
Stop
bushing
Seeger
ring
Stop
bushing
Seeger
ring
Stop
bushing
Seeger
ring
MHZ 315 T1 3700 3150 - - - T2 3900 3650
MHZ 355 T1 3400 3200 - - - T2 3850 3600
MHZ 400 T1 2950 2400 T2L 3200 2700 T2 3600 2900
MHZ 450 T1
2650 2400 T2L
2950 2700 T2 3230 2750
MHZ 500 T1
2200 1870 T2L
2500 2215 T2 2720 2275
MHZ 560 T1 2050 1800 T2L 2400 2200 T2 2600 2200
MHZ 630 T1 1650 1400 T2L 2100 1800 T2 2275 1850
MHZ 710 T1 1500 1350 T2L 1850 1750 T2 2015 1820
MHZ 800 T1 1200 1050 T2L 1500 1325 T2 1700 1425
MHZ 900 T1
1200 1050 T2L
1350 1250 T2 1500 1350
MHZ 1000 T1
1050 850 T2L
1150 1050 T2 1260 1150
MHZ 1120 T1 825 750 - - - T2 1175 1100
MHZ 1250 T1 765 650 - - - T2 1050 1000
AISI 304 and AISI 304 L EXECUTION
Max RPM limits are the same for execution with stop bushing and with seeger ring
Fan model arr. Max RPM arr. Max RPM arr. Max RPM
MHZ 315 T1 3145 - - T2 3315
MHZ 355 T1 2890 - - T2 3275
MHZ 400 T1 2510 T2L 2700 T2 3060
MHZ 450 T1 2255 T2L 2510 T2 2745
MHZ 500 T1 1870 T2L 2125 T2 2310
MHZ 560 T1 1745 T2L 2040 T2 2210
MHZ 630 T1 1405 T2L 1785 T2 1935
MHZ 710 T1 1275 T2L 1575 T2 1710
MHZ 800 T1 1020 T2L 1275 T2 1445
MHZ 900 T1 1020 T2L 1150 T2 1275
MHZ 1000 T1 895 T2L 980 T2 1070
MHZ 1120 T1 700 - - T2 1000
MHZ 1250 T1 650 - - T2 895
AISI 316 and AISI 316 L EXECUTION
Max RPM limits are the same for execution with stop bushing and with seeger ring
Fan model arr. Max RPM arr. Max RPM arr. Max RPM
MHZ 315 T1 2775 - - T2 2925
MHZ 355 T1 2550 - - T2 2890
MHZ 400 T1 2215 T2L 2400 T2 2700
MHZ 450 T1 1990 T2L 2215 T2 2425
MHZ 500 T1 1650 T2L 1875 T2 2040
MHZ 560 T1 1540 T2L 1800 T2 1950
MHZ 630 T1 1240 T2L 1575 T2 1705
MHZ 710 T1 1125 T2L 1390 T2 1510
MHZ 800 T1 900 T2L 1125 T2 1275
MHZ 900 T1 900 T2L 1015 T2 1125
MHZ 1000 T1 790 T2L 865 T2 945
MHZ 1120 T1 620 - - T2 880
MHZ 1250 T1 575 - - T2 790

Operating and Maintenance Manual - Air Conditioning Division
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11/42
Duplex
Fan Model arr
Max RPM
arr
Max RPM
arr
Max RPM
Stop
bushing
Seeger
ring
Stop
bushing
Seeger
ring
Stop
bushing
Seeger
ring
MHZ 315 T1 3700 3150 - - - T2 3900 3650
MHZ 355 T1 3400 3200 - - - T2 3850 3600
MHZ 400 T1 2950 2400 T2L 3200 2700 T2 3600 2900
MHZ 450 T1 2650 2400 T2L 2950 2700 T2 3230 2750
MHZ 500 T1 2200 1870 T2L 2500 2215 T2 2720 2275
MHZ 560 T1
2050 1800 T2L
2400 2200 T2 2600 2200
MHZ 630 T1
1650 1400 T2L
2100 1800 T2 2275 1850
MHZ 710 T1 1500 1350 T2L 1850 1750 T2 2015 1820
MHZ 800 T1 1200 1050 T2L 1500 1325 T2 1700 1425
MHZ 900 T1 1200 1050 T2L 1350 1250 T2 1500 1350
MHZ 1000 T1
1050 850 T2L
1150 1050 T2 1260 1150
MHZ 1120 T1
825 750 - - - T2 1175 1100
MHZ 1250 T1 765 650 - - - T2 1050 1000
-- Casing
According to MAZ and MHZ Technical Documentation deposited by the Notified Body, casing of
MAZ and MHZ fans are manufactured in black steel and painted or in AISI 304, in AISI 304 L, in
AISI 316, in AISI 316 L or in Duplex SS2205.
Casing is continuously welded and reiforced with stiffeners intermittent welded.
Casing is provided with inspection door.
The standard EN 14986 requires that the inspection door, outlet and inlet joints and eventual
holes in the casing for the fixing screws shall be sealed. As a consequence the casing can be
considered as gas tight without release (or with reduced release); this could be an aim in the
single inlet fan series, but it is out of application in the double inlet fan series, as for the MAZ
Atex and MHZ Atex series, object of the Category 2G certification.
The fan shaft must be installed in a horizontal position.
-- Application limits as declared in the Technical Documentation deposited by the Notified Body.
Fans shall operate inside the field covered by the catalogue curves, the use of the fan outside
this field could generate instability and vibrations;
for some fans, a part of the catalogue curve is drawn as a dashed line; this means that the use
of the fan in these conditions could generate instability and vibrations, due to the presence of
inlet obstructions (pulley, etc):
therefore in Atex application the fan must absolutely NOT be used outside catalogue field and in
the zone of dashed-line curves.
MAZ Atex, MHZ Atex.
absolute pressure from 0.8 bar to 1.1 bar;
aerodynamic energy increase of less than 25 kJ/kg;
atmospheres with a maximum 21 vol% oxygen content;
maximal temperature range of conveyed fluid between -20 and +60 °C
(except. from more stringent limits according to the motor model and brand installed);
gas explosion Groups IIA and IIB;
temperature class T3
As already declared for all fans of this handbook: no for conveying fluids containing dust.
NPL Atex, NPA Atex
-- Structure with motor support base
NPL Atex and NPA Atex plenum fans for application in Group II Category 2G are in setting 4,
with structure supporting the motor and wheel installed on the motor shaft and are supplied
complete with all features and devices necessary to comply with the ATEX directive
requirements: no modifications are allowed because plenum fan must correspond with the
technical specification declared in the documentation deposited by the Notified Body.
Structure is manufactured in steel S235JR, AISI 304, AISI 304L, AISI 316, AISI 316L or Duplex.
Fixing screws and rivets are in steel 8.8, in AISI 304, AISI 304L, AISI 316, AISI 316L; screws
and rivets for fixing the copper linings are in brass.
Plenums are provided with inlet guards and protective enclosure at outlet side.
Inlet guard:
where customer gives no specification the guard is positioned between inlet-cone and panel; if
guard is outside it is of flat-surface type. In both cases the inlet surface of the structure is
level to allow any connection to plant ducting;
where there is the inlet flexible connection, guard can be installed in every position: between
inlet-cone and structure, between structure and flexible connection or upstream the flexible
connection.
NOTE: positioning of the guard upstream of the flexible connection allows better air
performances
Protective enclosure:
for size 250, 280 and 315 rear guard wall in front of the wheel is completely manufactured in
copper; for other sizes a copper plate is fixed inside the enclosure in front of the back-plate /
hub; a copper lining is fixed on the outward frame supporting the enclosure for sizes 400, 500
because wheel diameter is up to the frame dimensions. For NPA 630 plenum fan a copper
lining is fixed on the motor-support wall facing the wheel.
All screws used for fixing these copper anti-spark protections are of brass.
The protection is of rigid design in order to avoid risk of rubbing on the wheel, due to the use of
an appropriate thickness for the guard, stiffeners or by splitting the guard in smaller pieces (the
joints between pieces increase the rigidity).
-- Impeller - shaft attachment
All NPL Atex and NPA Atex plenum fans have impeller hub positive locked between the shaft
shoulder and a locking screw and washer at the tapped shaft end. The impeller shaft must be
installed in a horizontal position.

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-- Operational limits
Maximal permissible rotational speed of NPL Atex plenum fan series in dependence of the wheel material:
Fan model
Max RPM
Standard material
(S275JR, DC04,
S355JOWP)
AISI 304, AISI
304 L
AISI 316, AISI
316 L
Duplex
NPL 250 5200 4420 3900 5200
NPL 280 4735 4025 3551 4735
NPL 315 4315 3668 3236 4315
NPL 355 3825 3251 2869 3825
NPL 400 3400 2890 2550 3400
NPL 450 3025 2571 2269 3025
NPL 500 2720 2312 2040 2720
NPL 560 2430 2065 1822 2430
NPL 630 2150 1827 1612 2150
NPL 710 Cl.1 1600 1360 1200 1600
NPL 710 Cl.2 1915 1628 1436 1915
NPL 800 Cl.1 1400 1190 1050 1400
NPL 800 Cl.2 1700 1445 1275 1700
NPL 900 Cl.1 1250 1062 938 1250
NPL 900 Cl.2 1500 1275 1125 1500
NPL 1000 Cl.1 1050 893 788 1050
NPL 1000 Cl.2 1350 1148 1013 1350
NPL 1120 Cl.1 900 765 675 900
NPL 1120 Cl.2 1150 978 863 1150
NPL 1250 Cl.1 765 650 574 765
NPL 1250 Cl.2 1085 893 814 1085
Maximal permissible rotational speed of NPA Atex plenum fan series in dependence of the wheel material:
Fan model
Max RPM
Standard material
(S275JR, DC04,
S355JOWP)
AISI 304,
AISI 304 L
AISI 316, AISI
316 L
Duplex
NPA 315 4500 3825 3375 4500
NPA 355 4000 3400 3000 4000
NPA 400 3700 3145 2775 3700
NPA 450 3300 2805 2475 3300
NPA 500 2850 2423 2138 2850
NPA 560 2650 2253 1988 2650
NPA 630 2350 1998 1763 2350
NPA 710 2100 1785 1575 2100
NPA 800 1800 1530 1350 1800
NPA 900 1600 1360 1200 1600
NPA 1000 1400 1190 1050 1400
NPA 1120 1200 1020 900 1200
NPA 1250 1100 935 825 1100
-- Application limits as declared in the Technical Documentation deposited by the Notified Body
- absolute pressure from 0.8 to 1.1 bar;
- aerodynamic energy increase of less than 25 kJ/kg;
- maximal temperature range of conveyed fluid between -20 and +40 °C
(except. from more stringent limits according to the motor model and brand)
- maximum oxygen content both in the conveyed fluid and in the installation environment: 21
vol%;
gas explosion Groups IIA and IIB;
temperature class: the same as motor temperature class and quoted also on the plenum fan
label
As already declared for all fans and plenum fans of this handbook: no for conveying fluids
containing dust
2.5.4 Explosion risks
The following is the list of explosion risks which has been assessed for the fan and plenum fan
series dealt with in this manual. The division in “normal operation” and “expected malfunction”
is due to the different fan Category 3 and 2: for Category 3 only the ignition risks which can take
place during normal operation are considered; for Category 2 malfunctions must also be
considered and consequently the ignition protection.
Every type of ignition protection has a symbol (see table below), which is reported on the fan
label.
symbol Type of ignition protection
fr for a flow restricting enclosure
d for a flameproof enclosure
c * for constructional safety
b for control of ignition source
p for pressurized equipment
k for liquid immersion
g for inherent safety
* Most of the ignition protections for the fan series TZAF FF Atex, VTZ Atex, NTHZ Atex,
THLZ FF Atex, MAZ Atex, MHZ Atex, TLZ Atex, TLI Atex, TZAF Atex, THLZ Atex, HLZ
Atex, TLE Atex, THLE Atex, KHLE Atex, NPL Atex, NPA Atex, TE (in steel ) Atex are type
“c”.

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Ignition risk assessment
Potential ignition source Measures applied to prevent the source from becoming
effective Ignition protection used
Normal operation Expected malfunction
Selection of unsuitable fan /
plenum fan
Compare process requirements with fan label data
EN 14986 7.3; Operating and maintenance manual par.2.3,
2.4, 2.5.1, 2.5.3.3.
Transportation damage Instructions for transport EN 14986 7.2; Operating and maintenance manual par.3.
Storage damage Instructions for storage EN 14986 7.2; Operating and maintenance manual par.3.1.
General environmental
influences
Instructions concerning: environmental temperature,
humidity, environmental corrosiveness. Ex. painting, zinc-
coating, stainless steel
EN 13463-1. Constructional safety ‘c’; Operating and
maintenance manual par. 2.4, 2.5.3.2, 3.3.
Excessive fluid temperature Inlet temperature and heating limitation of the gas handled,
check the field of application
EN 14986 1; Operating and maintenance manual par.2.4,
2.5.2, 2.5.3.3.
Maximal fluid temperature
+60°C
If motor is in the flow of the conveyed fluid, it is necessary
the application of a specific motor allowed to operate at the
fluid temperature.
See motor and fan / plenum fan labels.
Contact between static and moving
components caused by fan casing
deformation
Rigid housing design, separation of ductwork by elastic
joints, correct belt tensioning.
EN 14986 4.6. Constructional safety ‘c’; Operating and
maintenance manual par. 2.5.3, 4.5, 6.4, 6.5.
Contact between static and moving
components caused of plenum fan
protective enclosure deformation
Rigid design of protective enclosure through appropriate
structure, guard thickness and rigidity achieved through the
use of stiffeners or by splitting the guard into smaller
pieces
EN 14986 par. 4.6; constructional safety ‘c’; Operating and
maintenance manual.
Contact between static and moving
components caused by thermal
deformation
Operating temperature limits EN 14986 1; See fan or plenum fan label.
Contact between static and moving
components caused by impeller
deformation or fault
Rigid impeller design, decrease of maximal revolving
velocity
EN 14986 par. 4.7; constructional safety ‘c’; Operating and
maintenance manual par. 2.3, 2.5.3.1, see fan or plenum
fan label.
Contact between static and moving
components caused by loosened
impeller
Locking of the hub on the shaft EN 14986 par. 4.21, 5.2; constructional safety ‘c’;
Operating and maintenance manual par.2.5.3.
Contact between static and moving
components caused by misalignment
and wear and tear
Minimum clearance guaranteed by the use of a check
template at the assembling.
Suitable material pairings
EN 14986 par. 4.15, 4.8.2. Constructional safety ‘c’;
Operating and maintenance manual par.2.5.3, 4.5, 6.8.
Contact between static and moving
components due to shafts gliding in
bearings
Locking of the bearing on the shaft Bearing manufacturer manual; Operating and maintenance
Manual par. 6.6.
Radial displacement of bearing
respect to the inlet-cone centerline
Tightening torques; elastic pin in bearings with pillow block
Constructional safety ‘c’; Operating and maintenance
manual par. 6.6.
Bearing failure Bearing specification Operating and maintenance manual Appendix.
Bearing failure Correct belt tensioning Operating and maintenance manual par.6.5.
Bearing failure Bearings lubrication, check the operating condition of the
bearing
Operating and maintenance manual par.6.6.

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Potential ignition source Measures applied to prevent the source from becoming
effective Ignition protection used
Normal operation Expected malfunction
Bearing failure Bearings replacement (Safe operational life depending on
fan category, see 2.5.3.2 and 2.5.3.3)
EN 14986 4.17; Operating and maintenance manual
par.2.5.3.2, 2.5.3.3, 3.3, 4.1, 4.3, 4.5, 5.1, 6.
Motor bearing failure with wheel
directly installed at motor shaft
Correct dimensioning of maximal applicable radial and
axial load of the motor
Manual / technical specifications of motor manufacturer.
Mechanical faults and fatigue Vibration control in order to avoid abnormal conditions EN 13463-1, EN 14986; Operating and maintenance
Manual par.2.3, 2.4, 2.5.3.1, 4.2, 4.5, 5.4, 6.
Weakening of materials and bridging
of gaps due to corrosion
Corrosion protection EN 14986; constructional safety ‘c’; Operating and
maintenance manual see par. 2.4, 2.5.3, 3.3, 4.1, 6.8.
Explosive atmosphere with
low ignition temperature due
to dust deposits
Check the ignition temperature of dust in comparison to
temperature class; application field of fan, instructions
concerning inspection, cleaning
EN 14986 4.14; constructional safety ‘c’; Operating and
maintenance manual par.2.4, 2.5.1, 2.5.3, 6.2, 6.8.
Surface temperature Maximum surface temperature as defined for fan /plenum
fan temperature class; check the label indication
EN 14986 4.4.2; Operating and maintenance manual
par.2.5.2, 2.5.3.3.
Slippage of belts causing temperature
increase
Correct belt tensioning EN 13463-5 7.2; Operating and maintenance manual
par.6.5.
Pulley, fan shaft, motor shaft, wheel
back-plate, wheel hub rubbing on
transmission guard / protective
enclosure
Applying tip extensions / linings or manufacturing
transmission guard / protective enclosure from material
pairings permitted
EN 13463-5, EN 14986 4.8; constructional safety ‘c’;
Operating and maintenance manual par.2.5.3, 4.5.
Contact between static and moving
components caused by breakage of
pipe ring of airflow measurement
device
Use of proper connections joining pipe pieces firmly
inserted and secure multipoint fixing of pipe ring on inlet-
cone
Constructional drawings and operating instructions.
Contact with foreign
particles which can cause
sparks or damage to the
protective devices
Protection against foreign particles EN 14986 4.24; constructional safety ‘c’; Operating and
maintenance manual par.2.5.3, 4.5.
Electrostatic ignition Electrostatic discharges by earthing EN 13463-1 11; Operating and maintenance manual par.
4.4, 4.5.
Electrostatic discharges in
connection with belts
Belt drive rules EN 13463-5; Operating and maintenance manual par.
2.5.3, 4.5.
Electrical components Electric installation instructions of electric equipment See reference manuals of electric devices.

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2.5.5 Caption of fan label for anti-spark execution
GROUP II, Category 3
Code number: fan code
Type: fan description
Production number + year + week: serial number
Project – item: customer project reference
Absorbed power: operating shaft power
MAX absorbed power: maximum permissible shaft power
Operating temperature: operating temperature of the fan
Operating temperature MIN: minimum permissible entrance temperature of the fluid
Operating temperature MAX: maximum permissible entrance temperature of the fluid
Operating speed: operating fan speed [RPM]
Operating speed MAX: maximum operating fan speed [RPM]
Volume: operating air flow
Total pressure: operating total fan pressure
Ex II 3 G c IIB T4 : II indicates the group, 3 the Category, G means that the fan can move
dust- free air or lightly dusty air, c indicates the type of safety measure adopted, IIB is fluid
type class, T4 the temperature class. NOTE: IIB indication means that application extends to
both IIA and IIB fluid classes.
Technical handbook reference: code and version of “OPERATING AND MAINTENANCE
MANUAL”.
GROUP II, Category 2
For a fan in Category 2, respect to the label of a fan in Category 3 (to which refer for the
detailed fields description), is compiled also the further field “Certificate No.” i.e. the
deposit number of technical documentation by the Accreditation Institute (notified body),
required for Group II, Category 2.
Note 1: The examples shows a generic label in English; the label applied on the specific fan, will be
printed in the language requested by the customer choose from: Italian, English, German, French.
Note 2: In case of the peculiar indication for the fluid type class as IIB + H, it means that fan / plenum
fan is suitable for application with the gases of class IIA, IIB and also for hydrogen.
To be remarked: NOT for the other gases belonging to class IIC, but ONLY for hydrogen.
2.6 Fans and Plenum Fans with spark-proof execution according to VDMA
24169
From the 1
st
July 2003 the entry in force of ATEX Directive 94/4/EC repealed every other
directives and national standards concerning the matter of potentially explosive
atmospheres in all Countries belonging to EU.
Specifically for fans and plenum fans, VDMA 24169 has to be considered not more in
force in the EU market and superseded by standard EN 14986, which is the harmonized
standard related to ATEX Directive within the scope of design of fans and plenum fans
working in potentially explosive atmospheres, so that fans and plenum fans put on the
market or put into service inside the EU must comply with EN 14986.
Note: EN 14986 includes the requirements of VDMA 24169 and therefore covers and
stands in for the whole application scope of VDMA 24169.

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3 HANDLING AND STORAGE
3.1 Receiving
Each fan and plenum fan is carefully checked before shipment.
When receiving a fan or plenum fan it is necessary to check the
conformity of the fan or plenum fan with the order (execution,
rotation, power and polarity of installed motor, fittings, etc.); after
installation we do not accept returns of non-compliant devices.
Furthermore it is necessary to verify that it has not been damaged during the transport,
especially the rotating and the electric parts. In case of damage, they must be immediately
noted on the delivery note and communicated to the forwarding agent. The lorry driver
must countersign the document so that any damage which occurred during the transport
can be reported to the insurance company. Comefri will not be responsible for the
transport and the handling of the device at the customer's premises.
3.2 Handling
The handling of the fans and plenum fans requires adequate care
and lifting tools as foreseen by Directive 2006/42/EC and
subsequent amendments according to the weight and packaging
of the device. Special care must be taken to ensure that the fan
and the plenum fan will never be lifted by the shaft ends, motor
transport eyebolts, bearing supports and inlet or outlet flanges.
Lifting points of the fans are the base frame, housing frames or lifting eyebolts, if available.
Before handling the fan, release the tension of the belts or completely remove the belts.
Lifting points of the plenum fans are the holes in the base plate of the structure (for middle
sizes) or the holes in the side bars of the base frame of the structure (for bigger sizes).
Never stack devices one on top of the other after they have been removed from the box.
Be careful of improper handling, though not damaging the device, often leads to the need
to rebalance the impeller.
Particular care must be taken in handling fans and plenum fans provided either with
special painting or special protective coatings and treatments for which a slight undetected
damage will always entail the absence of protection above the metal surface and therefore
it might be cause of very serious failures during operation. Any damage to protective
coatings caused during the transport is not covered by Comefri warranty.
The fan weights are indicated in the technical catalogue.
3.3 Storage
Store the fan or plenum fan properly to protect them against filth
and moisture. Corrosive atmospheres must be avoided. Use of a
tarpaulin to cover the device will aid in keeping it clean and dry.
Do not use plastic sheets, as they will promote condensation,
especially in hot and humid environments.
Permissible storage temperature range is between -20ºC and +45ºC.
Fans and/or plenum fans manufactured in special execution for low temperature, as
exception from the previous storage temperature range, can be stored down to a minimal
temperature of -50 °C; before start-up they shall be warmed-up gradually and slowly to the
operating temperature.
If the fans are stored for over 6 months, you must release the tension of the belts (or
completely remove the belts) and rotate the shaft manually from time to time in order to
allow better distribution of the grease inside the bearings. Keep the fan or plenum fan
away from machinery producing vibrations as it could stress the bearings.
4 INSTALLATION
Installation must be carried out by trained personnel in compliance
with these operating instructions.
See the technical documentation in the relative technical catalogue
for additional information (characteristic dimensions, distance and
diameter fixing holes, weight, etc…)
4.1 Checks prior to installation
► Check the maximum performance data (see par.2.3, 2.4) and the rotation direction
indicated on the fan plate, comparing these with the impeller rotation and the
rotating field of the motor, especially in the presence of an anti-rotation device.
► Check that all bolts are properly tightened. Tightening torques for bearings shall be
according to the manufacturer catalogue; the tightening torques for all the bolts on
the fan and plenum fans shall be according to the prescriptions of the technical bolt
handbooks.
► Check the integrity of the fan painting and of all the sealed parts. Take corrective
actions if necessary (i.e. retouching painting before going ahead with further
preparation phases).
► Rotate the impeller manually and make sure that is does not touch the inlet-cone or
the Forefinger
®
device. During this operation, check that the bearings do not show
any sign of irregular friction.
TLZ, TLI, TLE fans have the impeller with forward-curved blades. For these types of fan,
make sure that connection to the duct is in accordance with the requirements to be
respected in order to obtained the correct resistance of the circuit (considered in the
design phase for the selection of the fan) so that the motor will not be overloaded.
NTHZ, VTZ, THLZ FF, MHZ, THLZ, HLZ, THLE, KHLE fans, NPL, NPL ALU , TE, NPE
plenum fans have the impeller with backward-curved blades; TZAF FF, MAZ, TZAF fans,
NPA, NPA ALU , PEAF plenum fans have the impeller with backward-curved airfoil blades;
both these types of fans and plenum fans can work also with circuits showing a flow
resistance lower than expected without having the risk of burning the motor.

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4.2 Installation / Fixing
The type of installation must be considered when choosing the fan.
Special attention must be paid to fans and plenum fans which are to be
installed in atmospheres with a high humidity and critical temperature
level.
The fan and plenum fan must be firmly fixed to a foundation or steel base frame. They
must be fixed while avoiding any strain and deformation to the support structure. When
using a foundation and fixing bolts, spacers should be added to ensure perfect contact
between the fan or plenum fan and its base frame. Otherwise misalignment or bending
moments could occur inducing anomalous vibrations during operation. A reinforced
concrete foundation is considered ideal for mounting the fan and plenum fan. When
installing on steel structures or racks, the design must consider both the weight of the fan
or plenum fan and the dynamic forces generated by the electric motor/impeller rotation. It
is absolutely necessary that these structures have a minimum resonance frequency higher
than 50% of the fan or plenum fan rotation frequency. When installing on a concrete
foundation, its weight should be four times that of the rotating group in addition to that of
the electric motor (almost twice the weight of the complete fan or plenum fan unit).
No force or vibration must be transmitted to the support structure. To this purpose, use
adequate anti-vibration dampers and flexible couplings for ducting.
Incorrect fixing of the fan or plenum fan can affect its operation and generate dangerous
situations.
Safety devices removed from the machine must be reinstalled before the electrical
connections are made.
Standard Comefri fans and plenum fans are designed to work with the shaft in a horizontal
position. If the fan and plenum fan have to be used with a vertical shaft, it must be
specified when placing the order and the specific special version must be requested (for
spark-proof execution only the horizontal shaft is allowed)
For impellers of the plenum fan series NPL, NPL
ALU , NPA, NPA ALU , TE, NPE, PEAF
when supplied as impeller and inlet-cone unit as loose components check the correct
overlapping of the inlet-cone and impeller according to the catalogue of reference.
Plenum fans do not meet the provisions of the CE labelling (e.g. they have an impeller
without guards).
The fan and plenum fan must nevertheless be installed in accordance with CE
requirements.
It is available a series of protective devices, inlet and outlet guards, protective enclosures
for plenum fans in setting 4, which can be requested at the order confirmation in function
of the installation type and according to standard UNI EN ISO 13857. For NPL, NPL ALU ,
NPA, NPA ALU , TE, NPE, PEAF plenum fan series, when provided as impeller and inlet-
cone loose components, due to the unknown final installation, outlet protections have to be
manufactured by the customer. As indicated in the relevant Catalogue can be ordered a
prearrangement for the outlet protection, consisting of a supporting frame, fixed to the
plenum main structure.
For plenum fans in Atex execution look up at par. 2.5.3
4.3 Motor and Belt Drive
A baseframe shall be arranged, provided by Comefri or by customer/user to
allow a common base for motor and fan. It shall be of rigid design to assure
the relative positioning of the components and to withstand stresses as vibrations and belt
tension, which is function of motor power (see also par. 4.2).
Motor should be install to baseframe by means of a motor rail which allows belt tensioning
and proper alignment.
Minimum pulley diameter. The theoretical life L
10
can only be guaranteed if the diameter of
the pulley corresponds to a minimum value, e.g. if the permissible load of the bearings is
not exceeded.
Use our fan selection program Aeolus to choose the transmission. Otherwise refer to the
technical catalogues of the pulley/transmission manufacturers.
Make sure that the pulleys are properly aligned. Fit the belts and tension them according
to instructions (see 6.5)
If the fan is in spark-proof execution, see par. 4.5.
4.4 Electric wiring
The motor must be connected to the terminal board according to the
information provided by the manufacturer of the motor.
Motors with rated power up to 4kW can be direct started, while
for those with rated power beyond 4kW star/delta soft starting is
normally used.
The motor must be protected against overloading and particular care is
required when using motors with spark-proof protection or equipped with
thermistors. Damage caused by insufficient motor protection makes the
manufacturer's warranty null and void. The customer is responsible for
earthing the fan and plenum fan.
4.5 Spark-proof execution according to ATEX 94/9/CE for Fans and Plenum Fans
Fans and plenum fans in Atex execution are declared by Comefri to be in
compliance with Atex requirements: if alterations are made to the machinery without
prior consultations with Comefri, the declaration becomes invalid.
Devices in Group II Category 2G must be in agreement with Technical Documentation
deposited with the Notified Body.
CHECK that the spark-proof category of the fan corresponds to the hazardous zone (see
2.5.1).

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Fans
The fan is of a rigid design and this reduces the risk of deformation from accidental
impacts which could cause the impeller or rotating parts to come into contact with the
casing. Nevertheless depending on operating conditions, be careful to avoid accidental
impacts especially with the weaker parts of the casing. Arrange protective devices if
necessary.
Casing for single inlet fans in Category 2. The inspection door is sealed; the installer must
seal the inlet, outlet and all other couplings with a suitable sealing material or apply
gaskets. This does not apply for TZAF FF Atex, NTHZ Atex, MAZ Atex, MHZ Atex double
inlet fans with Atex Category 2 execution.
Plenum Fans
Plenum fans shall be protected by the inlet grid and by the protective enclosure around the
impeller as indicated in par. 2.5.3. The enclosure around the plenum fan is of a rigid
design and this reduces the risk of deformation from accidental impacts which could cause
the impeller or rotating parts to come into contact with the enclosure parts. Nevertheless
depending on operating conditions, be careful to avoid accidental impacts; arrange
protective devices if necessary.
Horizontal installation
Fans and plenum fans in Atex execution must be installed with the shaft horizontal.
Stationary and rotating parts
A potential explosion risk can come from an accidental contact between stationary and
rotating parts placed close one to another:
INLET-CONE and SHROUD
FOREFINGER
®
and SHROUD
SINGLE INLET WHEEL BACKPLATE and CASING SIDEPLATE
MOTOR SHAFT and PROTECTIVE ENCLOSURE OF PLENUM FAN
PLENUM FAN WHEEL (e.g. hub, back-plate) and PROTECTIVE ENCLOSURE
FAN SHAFT / MOTOR SHAFT / PULLEYS and TRANSMISSION GUARD
In par.2.5.3 are indicated the provisions arranged to prevent risk from accidental contact
as required by the relevant Standard.
Stationary parts facing rotating parts have been made of material pairings as described in
paragraph 2.5.3.1 and observing the clearance as described in par. 2.5.3.2 to satisfy Atex
Standard requirements.
The clearance values between inlet-cone and shroud are provided in the Appendix.
The clearance must be checked before commissioning after having tensioned the
belt.
Due attention must be paid to possible axial movements of all rotating elements (for ex.
pulley), that must be kept in position or protected against displacement.
NOTE: in Atex application cooling fans shall not be used (see par. 2.5.3.1).
Protections against foreign particles
As required by Standard EN 14986, the fan and plenum fan shall be protected against the
entry of foreign particles according to grade IP20 of EN 60529.
Fans:
fans are provided with proper inlet and outlet protective guards according to grade IP20
compliant with the Standard requirement.
Plenum fans:
Comefri standard Atex execution provides plenum fans in setting 4 equipped with the
proper protection guard at the inlet and the protective enclosure at the outlet according to
grade IP20 compliant with the Standard requirement. The guard of the protection
enclosure is fixed at the front panel of the structure and at an auxiliary frame provided
between motor and wheel (see sketch in the appendix).
These guards and protective enclosures shall not be tampered, nor substituted with others
of different type, causing the decay of the Comefri certification for Atex execution.
As exception fan or plenum fan can be supplied without protections provided both the
following conditions are respected:
- the customer has produced a written declaration where he states that upon analysis the
kind of installation has proved to be itself a guarantee of IP20 protection:
- the customer requires by writing in the commercial order not to supply the protections.
As warned in the Standard EN 14986, the presence of inlet and/or outlet duct is not itself a
guarantee of IP 20 protection, but the risk of entry of foreign particles is to be analyzed
anyway.
Vibrations (fans and plenum fans)
The completed fan and plenum fan must meet the vibration levels recommended by ISO
10816 and ISO 14694 as appropriate for its size and application. Vibration speed should
preferably be measured at the bearing cap for fans and at the motor for plenum fan.
For the correct installation avoiding vibrations, see par.4.2. Furthermore the following must
be considered.
For some fans, a part of the catalogue curve is drawn as a dashed line; this means that
the use of the fan in these conditions could generate instability and vibrations, due to the
presence of inlet obstructions (pulley, etc). Comefri recommends not to use the fan in this
zone, but it must absolutely NOT be used in this zone when spark-proof execution is
required.
Standards such as ISO 5801 and ISO 5802 prescribe the type of inlet and outlet ducting
connections which ensure a uniform speed at the fan inlet and consequently a low degree
of vibration. The fan and plenum fan must be installed in a way which avoids disturbances
or building up vibrations in the fan, plenum fan. Examples of improper installations:
sharp bends in the ducting near the inlet or outlet, unit walls too close to the fan
sideplates, obstructions due to unsuitable guards. These installation errors must
absolutely be avoided in anti-spark applications according to ATEX Directive.

Operating and Maintenance Manual - Air Conditioning Division
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accompanied by this manual.
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Power drive
If the fan is driven through belts, they must be electrically conductive, in order to be
incapable of developing an incendiary electrostatic discharge during operation according
to ISO 1813. The drive guard must be made of electrically conductive material so that,
according to the electrical earthing (described in the following paragraph), every part
(guard, pulley, belts) is electrically equipotential.
The material used in the construction of the belts must not allow combustion when a
naked flame is applied to it. In order for this material to meet requirements of the standard,
it must be tested according to the method described in ISO 1210. The piece must not be
completely burnt during the test nor continue to burn for longer than 15 s after removal of
the test flame.
V-belts must be declared by manufacturer to be compliant with Atex requirements.
The drive guard is critical due to the risk of contact between the rotating and fixed
components: see par. 2.5.3. For this reason a disc of material according to the standard
EN 14986 4.8.2 must be installed in the internal side of the guard in front of the pulleys
with an outside diameter at least from 5 to 10 mm greater than rotating part dimension;
clearance between the motor or fan shaft and the edge of the passage hole shall be 10 %
of the shaft diameter (minimum 2 mm and maximum 13 mm) (see par. 2.5.3.2).
The pulleys must be balanced according to ISO 10816 and ISO 14694 depending on their
size.
Earthing conductive parts
Comefri guarantees that all parts of the fan are electrically equipotential; the
fan must be earthed by the installer. Guards for transmission devices and for
coupling must be manufactured with conductive material.
Electrical equipment
All electrical equipment (such as drive motors and monitoring equipment) must comply
with Atex protective category appropriate for the fan.
The motor must comply with Atex standards and its Atex field of application must
correspond with the field of application of the fan or plenum fan: this means that it must be
provided with the same group, category, type of explosive atmosphere or superior and
guarantee the maximum surface temperature as the fan or plenum fan.
Group II Category 2.
It is duty of Comefri to install the motor on fans of Group II Category 2 before putting the
fan in the market. This allows that Atex execution complies with Comefri Atex certification
and these Atex execution features must be respected during successive maintenance
process.
In detail, Comefri certification for Group II Category 2 applies when motor is installed by
Comefri, both if motor is provided by Comefri or supplied by the customer to Comefri,
provided motor has the proper ATEX 2G certification and/or motor label with relevant
indications attesting the compliance with Directive 94/9/CE “Atex” Group II Category 2G.
NOTE: Comefri certification does NOT apply when customer install the motor or the motor
supplied to Comefri does not comply with Directive 94/9/CE “Atex” Group II Category 2G;
in this case therefore it is duty of the customer to deposit his own complete and specific
documentation to apply for the “ATEX 2G” certification of his so obtained final machinery,
with the issue of his own new certification number.
In the operational life, maintence which requires motor substitution can be carried on by
the customer/user without decay of Comefri Atex certification, provided maintenance is
performed according the proper prescriptions (see par. 6.8)
Electrical installation of the fans must comply with the requirements of standards EN
60079-14 and EN 50281-1-2.
The motor must be positioned so as to assure that adequate cooling air is available and
that the ventilation inlets cannot be blocked. We recommend installing circuit breakers.
Operation temperature range of the motor is generally from –20°C to +40°C according to
the motor model and brand, which is more restrictive than Atex Application temperature
range.
Particular care for plenum fans and fans where motor is installed in the airstream.
Motor temperature limits must comply temperature condition of the zone where motor is
installed.
5 START-UP
5.1 Safety checks
-Disconnect and secure all fan power connections at OFF.
-Check that all the mechanical and electrical safety devices
have been installed and connected.
-Check that protective devices as inlet and outlet guards,
protective enclosures, shaft guards, transmission guard are
fitted.
-Check that no foreign bodies are in the ducts and in the fan
(tools, small components etc.).
-Rotate the impeller by hand and make sure no parts rub.
-Check the alignment and parallelism of the pulleys and the tension of the belts.
-Power, voltage and frequency must be checked referring to the electric motor plate of
the fan.
-Inspection openings (if present) must be closed.
-If storing the fan for over six months, it will be necessary to remove the old grease
and proceed with re-lubrication according to the quantities and types reported on the
Technical Data Sheets or in Appendix.
-When fan and/or plenum fan have been stored at temperature lower than normal
storage temperature shall be let warming-up gradually and slowly before start-up (see
also par.3.3).
5.2 Test run
The fan and plenum fan should be switched on briefly to verify the direction
of rotation of the impeller which should correspond to that indicated by the
arrow.
Should the motor run in the wrong direction, swap any two of the three
electrical leads. Rotation direction of single phase motors can be swapped

Operating and Maintenance Manual - Air Conditioning Division
Make sure that the fan is always
accompanied by this manual.
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by exchanging internal connections, as described on the motor plate or wiring diagram.
Always observe the electrical safety instructions.
5.3 Checking current consumption
Upon reaching the operating speed of the fan, immediately measure the absorbed current
and compare it with the rated current indicated on the motor plate. In case of abnormal
current consumption, switch off the motor immediately.
5.4 Checking for smooth running
Check the smooth running of the fan. There should be no
unusual oscillations or vibrations. Check for unusual noise
of the bearings.
5.5 Checking V-belt drive
After one hour of continuous run, stop the fan and check that belt tensioning
is in accordance with par. 6.5 and, if necessary, re-tension the belts; after 3-4
days of operation check the V-belt tension once again.
6 MAINTENANCE
Operational performance data are indicated on the fan label:
maximum operating temperature, maximum shaft power, maximum rotational speed, and,
if required, operating data for the specific application - rated speed, volume, total pressure,
rated temperature and absorbed power.
For impellers of the NPL, NPL ALU , NPA, NPA ALU , TE, NPE, PEAF plenum fan series,
when supplied as loose components, impeller and inlet-cone unit, do not exceed the
maximum speed provided in the catalogue of reference.
6.1 Safety information
Before any maintenance operation on the fan, it is necessary to
make sure that:
- the motor is disconnected from the mains
- the impeller is stopped
- the surface temperature be checked to prevent burning
- uncontrolled running of the fan during maintenance is
impossible
- no hazardous debris or materials are inside the fan.
Only limited work may be carried out while the fans are in operating conditions and in
compliance with safety and accident prevention regulations (e.g. measuring vibrations).
Failure to comply with these points endangers the life of maintenance personnel.
6.2 Casing and impeller
Even with slightly dusty fluids, wear and filth can also be expected inside the casing and
on the impeller (corrosion, abrasions, stuck materials) which can cause vibrations.
Inspections and cleaning must be performed regularly. Their frequency must be fixed by
the operator according to individual operating conditions.
Do not use high pressure cleaners (steam cleaners).
6.3 Accessories
Flexible connections between the fan and plenum fan and parts of the installation must be
checked regularly. Unsealed couplings lead to breakdowns and danger due to leaking fluid
and must be replaced.
6.4 Checking rotating parts
Periodically check the alignment of the impeller on the shaft as well as
fixing conditions of the bolts. Make sure all the bolts on the fan are
tightened. The tightening torques must be according to the prescriptions of
bolt technical manuals. For bearing bolts the tightening torque values must comply with
the bearing manufacturer's catalogue.
6.5 Belt drive
Depending on the installation site and type of fan operation, it is recommended to check
the belt tension and their alignment regularly.
This is compulsory for Atex spark-proof applications according to EN 14986.
Operate only by means of the motor rails, if present.
Belt displacement E
a
(see scheme in fig.1) must be calculated according to the formula (1)
and the values mentioned in table 1 in the Appendix:
Ea≅(E * e) / 100 (1)
where:
e = distance between shaft centers
E = belt bending for distance between shaft centers of 100mm
Ea = belt bending
Fig.1 (Belt-Drive scheme)