BENSON HEATING G20 I2H User manual

BENSON CABINET
HEATER
NATURALGAS (G20 I2H)
PROPANE GAS (G31 I3P)
I N S T A L L A T I O N C O M M I S S I O N I N G
S E R V I C I N G
U S E R I N S T R U C T I O N S
July 2010
Issue 11
THIS MANUAL SHOULD BE LEFT WITH THE END USER .
TO ENSURE SERVICE AND MAINTENANCE INFORMATION IS AVAILABLE ON SITE

1.0 Compliance Notices 4
1.1 Certificates of Conformity 5
1.2 General Product Information 5
1.3 General Requirements 5
1.4 Delivery & Pre inspection 6
1.5 Warranty 6
2.0 Location & Positioning 7
2.1 Gas Supply 9
2.2 Electrical Supply 9
2.3 Air Supply 9
2.4 Minimum Space Requirements 12
2.5 Air Distribution System 12
2.6 Flue System 13
2.7 Flue Installation 17
3.0 Installation 17
3.1 Packaging & Siting 17
3.2 Flooring 17
3.3 Minimum Clearances 17
3.4 Assembly 17
3.5 Gas Installation & Connection 18
3.6 Electrical Installation & Connection 18
3.7 Air Distribution Installation 18
3.8 Warm Air Registers 18
3.9 Heater Control Installation 19
4.0 Commissioning 19
4.1 Pre test 19
4.2 Ignition 20
4.3 Air Delivery System 22
4.4 Hand Over 22
5.0 Servicing 23
5.1 Planned Servicing 23
5.2 Servicing procedure Major Components 23
5.3 Service Re commissioning 27
6.0 Fault Diagnosis By Flow Chart 28
7.0 Wiring Diagrams 30
8.0 Technical Data 36
CONTENTS
8.1 Cabinet Range Technical Data 39
9.0 Reference Documents Standards & Codes of Practice 43
9.1 Parts Listing 44

~ C O N T E N T S ~
S E C T I O N 1
1.0 Compliance Notices 4
1.1 Certificates of Conformity 5
1.2 General Product Information 5
1.3 General Requirements 5
1.4 Delivery & Pre-installation Checks 6
1.5 Warranty 6
2.0 Location & Positioning 7
2.1 Gas Supply 9
2.2 Electrical Supply 9
2.3 Air Supply 9
2.4 Minimum Space Requirements 12
2.5 Air Distribution System 12
2.6 Flue System 13
2.7 Flue Installation 13
3.0 Installation 16
3.1 Packaging & Siting 16
3.2 Flooring 16
3.3 Minimum Clearances 16
3.4 Assembly 16
3.5 Gas Installation and Connection 17
3.6 Electrical Installation & Connection 17
3.7 Air Distribution Installation 17
3.8 Warm Air Registers 17
3.9 Heater Control Installation 18
4.0 Commissioning 18
4.1 Pre-Test 18
4.2 Ignition 19
4.3 Air Delivery System 21
4.4 Hand Over 21
5.0 Servicing 22
5.1 Planned Servicing 22
5.2 Servicing Procedure - Major Component Parts 22
5.3 Servicing - Re-commissioning 25
6.0 Fault Diagnosis By Flow Charts 26
7.0 Wiring Diagrams by Model and Burner Type 28
8.0 Technical Data Net Efficiency Calculations 35
8.1 Benson Cabinet Range Data 36
9.0 Reference Documents Standards, Codes of Practice 39
9.1 Parts Listing 40
S E C T I O N 2
10.0 Introduction
10.1 Commissioning/hand over
10.2 Servicing
10.3 Start up procedure
10.4 Stop procedure
10.5 Shutdown procedure
10.6 Ventilation only
10.7 Lockout situations
10.8 Contact Information
I L L U S T R A T I O N S
Page No
Exploded view 8
Flue Systems 14-15
Fan and Motor Configurations 23
Fault Diagnosis Flow Charts 26
Wiring Diagrams 28
Any reference made to Laws, Standards, Directives , Codes of Practice or other
recommendations governing the application and installation of heating appliances and
which may be referred to in Brochures, Specifications, Quotations, and Installation,
Operation and Maintenance manuals is done so for information and guidance purposes only
and should only be considered valid at the time of the publication. Benson Heating cannot
be held responsible from any matters arising from the revision to or introduction of new
Laws, Standards, Directives, Codes of Practice or other recommendations.
IMPORTANT NOTICE TO INSTALLERS
Installers should satisfy themselves that the gas pipework installation is carried out in
accordance with all current legislation, Codes of Practice and
recommendations .
Additionally it may be necessary to protect the gas valves which form part of
the heater or burner assembly from potential pipe contamination particularly,
but not exclusively , where copper gas pipework is used.
In instances where copper pipework is to be used for all or part of a gas
pipework installation, including short length final connections then we advise
that installers consult with gas supplier or provider and satisfy themselves what
additional precautions may be necessary

1.0 Compliance notices
The Benson Gas fired Cabinet Heaters
detailed herewith are manufactured by
Benson Heating Within a strictly controlled
quality environment within the parameters of
ISO 9001.
These instructions are only valid if the
following country code is on the appliance
GB. IE. If this code is not present on the
appliance, it is necessary to refer to the
technical instructions which will provide the
necessary information concerning the
modification of then appliance to the
conditions of use for the country.
The Benson range has been tested and
assessed for compliance with the following
European Directives.
Gas Appliance Directive (90/396/ EEC)
Machinery Directive (89/392/EEC)
Low Voltage Directive (73/23/EEC)
& (93/68/EEC)
Electromagnetic Compatibility Directive
(89/336/EEC & 91/31/EEC)
Product Liability Directive (65/374/EEC)
The manufacturer has taken reasonable and
practical steps to ensure that Benson
Cabinet Heaters are safe and without risk
when properly used. These heaters should
therefore only be used in the manner and
purpose for which they were intended, and in
accordance with the recommendations
detailed herewith.
The heaters have been designed,
manufactured, assembled, inspected, and
tested, with safety and quality in mind, there
are certain basic precautions which the
installer and user should be aware of, and
they are strongly advised to read the
appropriate sections of the information pack
accompanying the heater, prior to installation
or use.
Benson Heating supports all new products
being supplied to their customers with a
comprehensive information pack; this clearly
defines mandatory instructions for the safe
installation, use, and maintenance, of the
appliance(s).
Where proprietary items are incorporated
into Benson Heating products, detailed
information and instructions are also
provided as part of the information pack.
It is the responsibility of the installer, owner,
user, or hirer, of such products supplied by
Benson Heating, to ensure that they are
familiar with the appropriate information/
manuals, supplied by the manufacturer, and
that they are suitably aware of the purpose of
the manuals and the safety instructions. In
addition, operators must be suitably trained
in the use of the appliance so as to ensure its
continued safe and efficient use.
Benson Heating has a commitment to
continuous improvement, and therefore
reserves the right to amend or change the
specification of the Cabinet Heater range
subject to compliance with the appropriate
European, national, and local regulations.
Contained within the text of the manual, the
words 'Caution' and 'Warning' are used to
highlight certain points.
Caution is used when failure to follow or
implement the instruction (s) can lead to
premature failure or damage to the heater or
its component parts.
Warning is used when failure to heed or
implement the instruction (s) can lead to not
only component damage, but also to a
hazardous situation being created where
there is a risk of personal injury.
NOTE
THE WARRANTY REGISTRATION CARD
SUPPLIED WITH THE HEATER MUST BE
COMPLETED AND RETURNED
TO BENSON HEATING ON COMPLETION
OF COMMISSIONING
Warranty claims made without this
condition being fulfilled will not be
processed
The Benson range of Gas fired Cabinet
Heaters conform to the following harmonised
standards;

BS EN 1020 Requirements for non
domestic gas fired forced convection air
heaters for space heating incorporating a fan
to assist transportation of combustion air
and/or combustion products.
BS EN 292 - Part 1 : 1991
Safety of Machinery - Basic Concepts,
General Principles for Design Basic
terminology, methodology
BS EN 292 - Part 2 : 1991
Safety of Machinery - Basic Concepts,
General Principles for Design
Technical Principles and Specifications
BS EN 60204 - Part 1 : 1993
Safety of Machinery - Electrical Equipment
for Machines Specification for General
Requirements
BS EN 60335 - Part 1 : 1988
Safety of Household and Similar Electrical
Appliances General Requirements
BS EN 55014 - 1993
Limits and methods of measurement of radio
disturbance characteristics of electrical
motor-operated and thermal appliances for
household and similar purposes, electrical
tools and similar electric apparatus
BS EN 50165 - 1997
Electrical Equipment of non-electric heating
appliances for household and similar
purposes, safety requirements
1.1 Certificates of conformity
Certificates are available from the Quality
Control Department at Benson Heating.
Notified body Pin reference is 63AQ0533.
1.2 General product information
The Benson range of indirect gas fired forced
convection heaters have an output range
from approximately 29.3 kW to 381.0 kW and
are available in a configuration that will allow
for down flow, horizontal, floor mounting, or
above ground level on purpose built steel
supports.
The units can suit either ducted applications,
or be used as free blowing units, but each
heater must be connected to its own
individual open flue.
Each heater is fitted with a forced draught
burner which has been test fired and pre-set
prior to despatch. The safety functions of the
burner are by way of a fully sequential
control box fitted to the burner.
Note
Neither asbestos nor soft soldered joints are
used in the construction or manufacture of
the Benson range of Cabinet Heaters. The
materials selected for use can withstand the
mechanical, chemical, and thermal stresses
which they will be subject to during foreseen
normal use when installed in accordance
with the manufacturers recommendations.
1.3 General requirements
Caution
Before installation, check that the local
distribution conditions, nature of gas and
pressure, and the current state adjustment of
the appliance are compatible.
Installation, commissioning, and servicing
must only be carried out by appropriately
qualified and competent persons.
Warning
Unauthorised modifications to the appliance,
or departure from the manufacturers
guidance on intended use, or, installation
contrary to the manufacturers
recommendations may constitute a hazard.
Note
To ignore the warning and caution notices,
and to ignore the advice from the
manufacturer on installation, commissioning,
servicing, or use, will jeopardise any
applicable warranty, moreover, such a
situation could also compromise the safe and
efficient running of the appliance itself, and
thereby constitute a hazard.
The installation of the appliance must meet
all the relevant European, national, and local
criteria. (See sections 3 and 9).
Prior to installation the following points
should be considered;

a) The position of the heater for the optimum
efficient distribution and circulation of warm
air
b) The position of the heater relative to the
route of the flue
c) The position of the heater relative to the
supply of gas
d) The position of the heater relative to the
electrical services, and if appropriate, any
additional controls.
e) The position of the heater relative to the
supply of fresh air
f) The height if applicable at which the heater
is to be mounted and potential stratification /
circulation problems.
g) The position of the heater relative to
service and maintenance requirements
Caution
The heater must not be installed within an
area where the conditions are unsuitable,
e.g. where the atmosphere is highly
corrosive, has a high degree of salinity, or
where high wind velocities may affect burner
operation. Suitable protection should be
provided for the appliance when it is located
in a position where it may be susceptible to
external mechanical damage from; for
example, fork lift trucks, overhead cranes
etc.
1.4 Delivery and pre-installation
checks
The heater is supplied wrapped in heavy
duty protective polythene. On receipt of the
heater, the following checks should be
carried out;
a) The model is as per order
b) That it is undamaged
c) That it is suitable for the fuel supply
d) That it is suitable for the electrical supply
If any of these points are not satisfied then
contact should be made with the Sales Office
at Benson Heating as soon as possible by
telephoning 01547-528534. In the case of
claims for damage, this must be signed for
as damaged and reported in writing within 24
hours of delivery, in order to comply with
insurance criteria
1.5 Warranty
The heater is supplied with a 2 year warranty
made up as follows; first year covering parts
and labour, and second year covering parts
only. In addition to this there is also a 10 year
time related warranty on the combustion
chamber/heat exchanger. The warranty
commences from the date of despatch from
the manufacturer, and is subject to the terms
detailed within the Benson Heating
'conditions of business'.
Note (i)
The warranty may be invalidated if -
a) The warranty registration/commissioning
card has not been completed and returned to
Benson Heating
b) The installation is not in accordance with
the general requirements of this manual
c) The flue arrangement and air supply for
the heater are not in accordance with the
manufacturers
recommendations, codes of practice, or
similar standards
d) Air flow through the heater is not in
accordance with the manufacturers technical
specifications
e) Internal wiring on the heater has been
tampered with or unauthorised service or
repairs undertaken
f) The main electrical supply input to the
heater has been interrupted during the
heating mode
g) The heater has been subject to and
affected by the ingress of water in any form
h) The heater is not operated at the rating(s)
laid down in the manufacturers technical
specifications
i) The heater has not been operated or used
within the normal scope of its intended
application

j) The manufacturer's recommended
minimum service requirements have not
been complied with
Note (ii)
All warranty claims must contain the
following information to enable processing to
take place;
(1) Heater model
(2) Heater serial number
(3) Order reference/date of order, together
with full installation details (name and
address)
(4) Details or symptoms of fault
(5) Installers name and address.
Faulty parts must be returned to the Knighton
Spares Department, the address of which is
provided in Section 2 of this manual. Any
such parts will undergo inspection to verify
the claim. Replacement parts supplied prior
to this may be charged, and a credit supplied
upon subsequent validation of the warranty
claim.
Consumable items are specifically not
included within the scope of the warranty.
Note (iii)
Notification is required immediately a fault is
suspected.
The manufacturer will not accept
responsibility for any additional damage that
has been caused, expense incurred, or
consequential loss resulting from any failure
of the heater(s).
2.0 Location / Positioning
Warning
All of the basic criteria must be satisfied prior
to commencing installation and
commissioning, additionally, the Cabinet
Heater must be positioned and installed so
as to comply with all the relevant standards
and guide lines (see section 9.0), as well as
meeting national and local fire regulations
and insurance criteria, especially if it is
proposed that the heater is to be installed
within a special risk area (e.g. proximity to
where petrol engined vehicles are stored or
parked, where cellulose spraying takes
place, where woodworking machinery is
operated, etc,).
Indirect fired heaters must not be located in
hazardous areas, however, it is permissible
for the heater to supply air to such areas.
The heater must not be installed within an
environment where there is a high
concentration of chlorides, fluorides, salts, or
other aggressive or volatile chemicals /
compounds. Nor should the heater be
positioned where the burner could be
adversely affected by high winds or draughts.
The location chosen for the heater must
allow for the fitting of an effective flue
system.
The location must also allow for adequate
clearance for the air supply, return air
circulation, oil supply, electrical supply, whilst
also providing good and safe working
access. The heater must be installed on a
flat and level surface made from non-
combustible material, which is sufficiently
robust to withstand the weight of the heater
and any ancillary equipment. Any
combustible material adjacent to the heater
or flue system must be so placed or shielded
so that its surface temperature does not
exceed 65oC.
In areas where it is proposed that more than
one heater is to be installed, a general
scheme of circulation should be drawn up
and maintained, thereby offering the best
heat distribution.
All Benson Heaters are fitted with a pressure
relief facility, this is incorporated into the
design of the flue gas exit duct. Care should
therefore be taken in siting service
connections and controls well away from the
pressure relief vent.
Warning
Under no circumstances must the pressure
relief be restricted, blocked, or have the free
exit of exhaust gas impaired or re-directed.

2.1 Gas supply - general
The Benson range of gas fired cabinet
heaters are all manufactured and pre-set for
use with natural gas or LPG classified under
the categories, based upon the destination of
the heater see section 8.0
The heater must be compatible with the gas
supply, and each heater must be installed
with a separate approved isolating gas cock
positioned adjacent to and upstream of the
union between the service pipe and the
heater.
The gas supplier should have been
contacted to confirm that the supply feed
(pipework and metering) is capable of
delivering the required dynamic volume of
gas, thereby ensuring that the minimum
burner pressure can be achieved.
Consideration should have also been given
to the pressure drop on single and multiple
heater installations, and the affect that such
installations will have upon other plant
sharing the gas supply.
If it is necessary to fit a gas booster, the
controls must include a low pressure cut-off
switch which must be fitted on the supply
side of the booster. It is also a requirement
that the gas supplier is contacted prior to the
fitting of the unit.
Note
Reference to the Institute of Gas Engineers
publication UP-1 and UP-2 together with
BS6891 is strongly advised.
Service and Installation pipework must be of
a diameter equal to or greater than the inlet
connection on the heater, all joints must be
sealed using an approved sealing
compound, and the system purged and
tested for soundness.
2.2 Electrical supply
Wiring external to the cabinet heater must be
installed in accordance with any local,
national, and European regulations, as well
as meeting the appropriate requirements of
IEE regulations.
The means of connection to the main
electrical supply must allow for complete
electrical isolation of the heater, furthermore,
in the case of a unit wired for a three phase
supply, the supply should only be used to
serve the heater itself and no other plant or
equipment.
The position of the isolation switch must be
such that it is adjacent to the heater and
easily accessible at all times. In addition, the
isolator itself must have a contact separation
of not less than 3mm as per BS5991
clause 20.2.
The Control Fuse ratings are detailed on the
appliance data plate.
Warning Ensure that the electric and gas
supplies are turned off before any electrical
work is carried out on the heater. Ensure
that wiring cannot make contact with any
surfaces liable to be subject to high
temperatures or where the insulation of the
wiring could be impaired as a result of such
contact.
All Cabinet Heaters must be earthed.
Caution
The main electrical supply must not be
switched off or disconnected as a method for
stopping the heater, the exception to this is in
an emergency, or during servicing, when the
heat exchanger has been allowed to cool
sufficiently to prevent any damage from
occurring. Claims for damage will not be
considered if they have resulted from
incorrect wiring or the incorrect use of the
heater.
2.3 Air supply
Consideration must be given to the provision
of air for the purposes of combustion and
ventilation of the heated space, plant room or
enclosure where heaters are to be installed
Note
It is strongly recommended that BS 6230 :
2005 is referred to for further information
concerning ventilation requirements
Where mechanical ventilation is used it is a
requirement that the inlet is of the
mechanical type, and the outlet is either
mechanical or natural.

2.3.1 Heaters installed within the
heated space
Where heaters are installed within the space
to be heated (I.e. not a plant room or
enclosure
Combustion air or heater related ventilation
air
Will not be required if
The design air change rate of the heated
space is 0.5 air changes per hour or greater
The design air change rate may be satisfied
by natural infiltration or by mechanical
ventilation
Combustion and General ventilation
will be required if
The design air change rate of the heated
space is less than 0.5 air changes per hour
Where the heated space has an air change
rate of less than 0.5 air changes per hour
then it will be necessary to provide either
natural ventilation openings to the heated
space (section 2.3.1.1. refers) or the
mechanical ventilation of the heated space
(section 2.3.1.2. refers)
2.3.1.1 Natural Ventilation Openings to
the Heated Space
If the heated space design air change rate is
less than 0.5 air changes per hour then
provision for low level natural ventilation
openings will only be necessary
The minimum free area of the low level
natural ventilation opening shall be
 2cm2for each kW of rated heat input
The low level natural ventilation opening
should be situated on an external wall and be
within 1000 mm of floor level for natural gas
and ideally at floor level for l.p.g gas
installations but in any event no higher than
250 mm.
The table in the next column provides
specific data for each heater model as -
2.3.1.2
Mechanical Ventilation to the Heated
Space
In the event that the heated space has a
design air change of less than 0.5 air
changes per hour and that installer prefers to
mechanically ventilate the heated space
rather than provide ventilation openings then
-
 The heated space needs to be
mechanically ventilated so that the
design air change is 0.5 air changes or
greater.
 It is a requirement that the mechanical
ventilation shall be of the ’input’ type
with either natural or mechanical
extraction.
 Systems of mechanical extraction with
a natural inlet shall not be used
 It is necessary to provide an automatic
means to safely inhibit heater(s)
operation should mechanical air supply
fail for any reason
Minimum Free Area of
ventilation opening
High Level Low Level
cm2cm2
100 None 64
125 None 79
150 None 97
200 None 127
250 None 160
300 None 193
400 None 257
500 None 291
600 None 386
700 None 460
800 None 515
1000 None 623
1200 None 769
1300 None 847
Model

2.3.2. Heaters Installed within a Plant
Room or Enclosure
A plant room means a room housing the
heater plant and probably other items of
building service plant and would generally
have generous space for maintenance
An enclosure is where the heater is installed
within a compartment or confined area where
space is limited
Where heaters are installed within a plant
room or enclosure then provision for both
combustion air and air for general ventilation
will be required by means of high and low
level ventilation openings (sections 2.3.2.1
refers to plant room applications and
sections 2.3.2.2 refers to enclosure
applications).
Alternatively the plant room or enclosure may
be mechanically ventilated (section 2.3.2.3
refers)
2.3.2.1 Natural Ventilation Openings to
Plant Rooms
For plant room applications the minimum free
area of ventilation opening shall be
 At high level 2 cm2for each kW of
rated heat input
 At low level 4 cm2for each kW of rated
heat input
The high level ventilation opening should be
sited on an external wall and positioned as
high as is practical and always within the top
15% of the wall height
The low level natural ventilation opening
should be situated on an external wall and be
within 1000 mm of floor level for natural gas
and ideally at floor level for l.p.g gas
installations but in any event no higher than
250 mm.
The table below provides specific data for
each heater model as -
2.3.2.2 Natural Ventilation Openings to
Enclosures
For enclosure applications the minimum free
area of ventilation opening shall be
 At high level 5 cm2for each kW of
rated heat input
 At low level 10 cm2 for each kW of
rated heat input

The high level ventilation opening should be
sited on an external wall and positioned as
high as is practical and always within the top
15% of the wall height
The low level natural ventilation opening
should be situated on an external wall and be
within 1000 mm of floor level for natural gas
and ideally at floor level for l.p.g gas
installations but in any event no higher than
250 mm.
The table below provides specific data for
each heater model as
Minimum Free Area of
ventilation opening
High Level Low Level
cm2cm2
100 64 128
125 79 158
150 97 194
200 127 254
250 160 320
300 193 386
400 257 514
500 291 582
600 386 722
700 460 920
800 515 1030
1000 623 1246
1200 769 1538
1300 847 1694
Model

2.3.2.3 Mechanical Ventilation to a
Plant Room or Enclosure
In the event that the installer prefers to
mechanically ventilate the plant room or
enclosure rather than provide ventilation
openings then -
 The plant room or enclosure needs to
be mechanically ventilated at the rate
of 4.14 m3/h of fresh air per kW or
rated heat input.
 It is a requirement that the mechanical
ventilation shall be of the ’input’ type
with either natural or mechanical
extraction. Where mechanical
extraction is selected then the
extraction rate should be 5%-10% less
than the input rate.
 Systems of mechanical extraction with
a natural inlet shall not be used
 It is necessary to provide an automatic
means to safely inhibit heater(s)
operation should mechanical air supply
fail for any reason

The table below provides specific data for
each heater model as -
2.4 Minimum space requirements
The minimum space requirements for single
and multiple heater applications are detailed
in section 3.3 later within this manual.
2.5 Air distribution system
All materials used within the construction of
the delivery and return air ducts must not
represent a fire hazard and should be made
from thermally inert materials. The selection
of materials must take account of the
environment into which the heater and its air
delivery system is expected to work, it must
also take account of the stresses and
loadings placed upon it during its normal
working life Where interjoist spaces are used
to route ducting these must be lined with fire
resistant insulation material.
In installations where forced recirculation is a
Minimum Free Area of
ventilation opening
High Level Low Level
cm2cm2
100 159 318
125 198 396
150 244 488
200 317 634
250 400 800
300 483 966
400 643 1286
500 726 1452
600 965 1930
700 1152 2304
800 1287 2574
1000 1558 3116
1200 1922 3844
1300 2118 4236
Model
MODEL Mechanical Ventilation Rate for
Plant Room or
Enclosure
125 164
150 202
200 262
250 331
300 400
400 533
500 601
600 799
700 954
800 1066
1000 1290
1200 1592
1300 1753
100 132
M3/h

feature, a full and unobstructed return air
path to the heater(s) must be provided, with
return air grilles connected by ducting directly
to the return air inlet on the heater. The limit
for recirculation should not be greater than
85% recirculated air to 15% fresh air.
Where the heater is installed within a
enclosure or plant room the return air and
discharge air arrangement must be such that
the air circulation fan does not interfere with
the operation of the flue. The return air intake
and warm air outlet should therefore be fully
ducted to and from the heater, respectively,
within the compartment or plant room.
If the inlet air is ducted to the outside, then
the lowest edge of the inlet air duct must be
at least 500 mm above the outside floor or
ground level, it must also be fitted with an
access point (s) to allow for cleaning and
servicing to occur. The openings in the
structure of the plant room, through which
the ductwork passes must be of fire resistant
material and constructed to prevent the
likelihood of any fire from spreading.
In ducted applications the ductwork must be
designed so as to give a static pressure
within the limits stated in section 8 of this
manual. It should be noted that if the static
pressure is too high, nuisance shut-down will
occur when the heater goes out on the
overheat limit thermostat, if the static
pressure is too low, then damage can be
caused to the fan motor.
Warm air outlets on ducted applications must
be such that they cannot be closed or
become blocked, which again would lead to
an increase in static pressure and nuisance
shutdown.
The outlets must not be sited so that warm
air can be discharged onto combustible
materials, if necessary, guard rails should be
used to ensure that effected areas are kept
clear. Return air intakes must not be located
so that potentially harmful or hazardous
contaminated air can be drawn into the
system.
2.6 Flue system
It is essential that the products of combustion
are flued to the outside of the building. Each
heater must have its own separate flue, with
a flue diameter of not less than is detailed in
section 8 within this manual.
the minimum vertical length of flue must not
be less than 3m. The flue should rise
vertically, and the number of bends should
be kept to a minimum.
Flue pipe should be supported at intervals
not exceeding 1.8mtrs
Flue pipes below a height of 2 m should
be guarded against the possibility of
being accidentally touched when hot by
personnel
It is strongly advised that BS 5854; 1980,
and BS 5440; parts 1 and 2, are used as
consultative documents when considering
flue requirements.
Care should be taken to ensure that the flue
terminal is not situated in a high pressure
area, the proximity of buildings and other
obstacles which will influence this must be
taken into account, preferably at the design
stage. See figures 2-12.
Provision must be made for the
disconnection of the flue for inspection and
service requirements, and it is strongly
advised that where bends are fitted
inspection covers are included. The materials
from which the flue is constructed must be
non-combustible, resistant to internal and
external corrosion, and be capable of
withstanding the stresses and loadings
associated with normal use.
When designing the flue system the
prevention of the formation and entrapment
of condensation must be a key consideration.
Twin wall or insulated systems are
recommended as they tend to inhibit the
formation of condensates.
Where condensation is unavoidable traps
should be included to encourage the
condensates to flow freely to a point from
which they may be released, preferably into
a gully. The condensate pipe from the flue to
the disposal point must be made from
corrosion resistant pipe of not less than
25 mm internal diameter.

If the flue passes through a wall, ceiling, or
roof made from combustible material then it
has to be sleeved so as to provide a
minimum of a 25 mm void between the
exterior of the flue and the internal wall of the
sleeve. The maximum permitted temperature
of any adjacent combustible material is 65oC.
The position of the flue and its terminal
should be such that it does not impair the
combustion process.
It should terminate in an exposed position so
as to allow the escape and dissipation of flue
gases without risk of their re-entering the
property through windows, ventilation ports,
etc,.
The flue should extend to at least 1m above
the height of any object within 3,5m of the
terminal.
Flue terminals should be fitted on all flues
with a diameter of 200 mm or less. The
terminal must be of the approved type, and
have outlet grilles on all sides giving a total
free area of at least double that of the flue.
Caution
It is imperative that the flue should be
properly sealed where it passes through the
roof, this can best be achieved by using the
approved method of roof flashing plate and
cravat.
Note
It should be noted that claims made under
warranty and attributed to the ingress of
water may not be considered especially if an
approved method of sealing has not been
used, or if the design of the flue has not
made provision for possible condensation
problems

Not less than
600mm
Not less than
600mm
Greater than 1500mm
Parapet
Not less than
600mm
Less than 10 h
Greater than 1500mm
H
1
H
2
2
Less than 10 h
1
Flat roof with parapet
Flat roof envelope method
Structure
Not less than
250mm
2
Greater than 10 h
1
H
1
H
2
Structure
Flat roof where the flue height is more than 10 Heights (H) away from all structures
Structure
Not less than
600mm
Less than 1500mm
Flat roof with flue close to parapet

Not less than
600mm
Less than
1500m
m
Structure
Flat roof with structure close to flue outlet
Pitched roof not greater than 45°
Not less than
600mm
Not greater than
45
°
Not less tha
n
600mm
Not less than
600mm
Not less than
250mm
Flat roof with no parapet

2.7 Flue Installation
An integral flue spigot is fitted to all Cabinet
Heaters thereby allowing the flue to connect
directly to the heater. The design of the flue
must ensure that it can be disconnected to
allow for cleaning and servicing, furthermore,
all of the flue section joint sockets must face
upwards, and the seal between the sections
achieved through mechanical joints or
through the use of approved caulking string
and grout. It is strongly advised that BS 5854
and BS 5440 parts 1 and 2 are referred to,
see also figs 2-12.
Where condensation is likely to be a problem
provision should be made preferably at the
design stage (see section 2.5).
3.0 Installation
It is strongly advised that the installer reads
Section 2 and Section 3 of this manual prior
to starting any installation work. It is a
requirement that only qualified and
competent personnel may undertake
installation, commissioning, and servicing.
Warning
Always ensure that the appropriate personal
protective equipment is used.
3.1 Packaging/siting
The heater will usually be supplied wrapped
in polythene, non assembled parts will be
supplied separately. Prior to installation, the
assembly of the heater should be completed,
it is advisable that this is undertaken in the
area where the heater is scheduled to be
sited.
Caution
It is strongly advised that when positioning
the heater the lifting eyes are used, thereby
reducing the risk of inadvertent damage
being occasioned to the heater.
3.2 Flooring
The heater must be installed on a level non
combustible surface capable of supporting
the weight of the heater and any ancillary
equipment.
3.3 Minimum clearances
The following minimum clearances (in
millimeters) must be observed when
installing the heater.
3.4 Assembly
The following sub-assembly parts should be
assembled to allow installation to continue.
(a) Vertical Nozzled Models
For free blowing applications it will be
necessary to complete the final assembly
before continuing with the installation. The
bonnet top with nozzle spigots should be
attached to the heater and secured. The
nozzles should then be pushed home on the
spigots and positioned to provide the desired
airflow.
Ensure louvres are adjusted outwards
and ensure blades are not resonating
The nozzles should be securely fixed in their
desired position on completion of
commissioning.
(b) Horizontal Nozzled Models
Remove packaging and secure the 90o Duct
Outlet to the outlet on the heater using the
bolts supplied.
Secure the nozzle spigot plate to the duct
outlet using the bolts and prevailing torque
nuts provided. Fit the securing brackets to
each of the outlet nozzles, and lift the
complete heater assembly and position on
the pre-sited purpose built supports. Finish
off the assembly by fitting and securing the
outlet nozzles to the spigots by way of
previously fitted brackets.
Model Size Front Rear Lhs Rhs
100 -150 500 700 150 150
200 - 300 500 1,000 150 150
400 - 500 600 1,200 150 150
600 600 1,500 150 150
700 900 1,500 150 150
800 - 1000 900 2,000 400 400
1200-1300 900 2,000 500 500

3.5 Gas Installation/Connection
Service pipework must terminate at an
approved gas cock, and be adjacent to the
position of the heater.
The connection to the heater can be made
by way of either an approved flexible
coupling, or rigid connection. Threaded
connections must comply with ISO288/1 or
ISO 7/1, further information concerning the
accepted practice in European countries is
detailed in the June 1995 version of prEN
1020 annex A7 The diameter of the pipework
from the cock to the burner connection must
not be less than the diameter of the burner
connection inlet. (see section 8 )
The installation must be purged and tested
for soundness prior to commissioning.
Always ensure that the appropriate personal
protective equipment is used.
3.6 Electrical Installation/Connection
Benson cabinet heaters are available either
for 415V 50Hz 3PH or 230V 50Hz 1PH
supplies depending upon the model
specified.
It is recommended that reference is made to
the wiring diagrams contained within section
7 of this manual prior to installation or
connection to the supply.
The electrical supply must be as specified
and suitable for the heater, and must be run
within conduit to a point adjacent to the
heater, and be terminated to provide an
isolation point that will prevent remote or
inadvertent activation. Cables, conduit, and
fittings that are used to make the connection
between the isolator and the heater must
conform to the appropriate IEE regulations.
All heaters are supplied fused and pre-wired,
all must be earthed.
Final connections for any additional external
controls must be completed on site, and
must be carried out according to IEE
regulations. Separate user information is
provided for the time control unit and the
burner, and forms part of the product
information pack which accompanies every
heater when despatched.
Warning
Always isolate from mains electrical supply
before commencing work on the heater.
Always ensure that the appropriate personal
protective equipment is used.
3.7 Air Distribution Installation
The materials selected must be of low heat
capacity, and it is preferable that all warm air
ductwork is thermally insulated.
Where ducting may be subject to
deterioration from exposure to moisture or
high humidity material selection and
insulation are prime considerations.
Joints and seams must be airtight and
fastened securely and designed to remain
so, even when operating at high
temperatures. Adequate support must be
designed into the layout of the ductwork to
ensure that the integrity of the seams and
joints is maintained.
The support must be independent and
separate from the heater and the ducting, to
allow for free movement during expansion
and contraction.
Where ducting passes through walls or
partitions sufficient clearance must be left,
irrespective of any fire stop requirement, to
allow for expansion and contraction Failure
to adhere to these latter two points can result
in the generation and transmission of excess
noise.
Where ducting is installed in concrete
flooring a permanent membrane must be
used to isolate the ducting from the corrosive
effect of the alkaline salts within the
concrete. Care should be taken to ensure
that soft insulation material does not become
compressed and thereby lose its
effectiveness.
3.8 Warm Air Registers
In order that vertical temperature gradients
are minimal thereby providing a more even
heat distribution, it is preferable to install
warm air registers at low wall levels or at
floor level, with the size, number, and
position commensurate with the requirement
of the application.

To minimise noise levels the registers should
be set away from corners, additionally, a good
seal between the register frame and the wall
is important, particularly on high level
positions, if unsightly staining through warm
air/ particulate deposition is to be avoided.
3.9 Heater Control Installation
Warning
Isolate heater from mains before undertaking
any electrical work.
Unless specified all Cabinet Heaters from 100
to 1300 are manufactured and supplied with a
CP2 Control as standard .
The following controls fitted and pre-wired
(a) On/standby switch
(b) Ventilation/heat switch (summer/winter
switch)
(c) Manual/automatic switch
(d) Thermostat
(e) Time clock
(f) Frost stat
A CP4 Controller is available as an option
All of the above controls are located on a
removable panel which when separated from
the heater can be re-positioned so as to offer
a remote facility.
However, to facilitate this, it is necessary to
order and fit an electrical panel cover and
front panel blanking plate to the heater in
place of the control unit.
The controls for Horizontal Cabinets are
supplied as remote option.
4.0 Commissioning
It is a requirement that only suitably
qualified and competent personnel are
allowed to undertake the
commissioning of the heater.
It is also strongly recommended that prior to
commissioning the engineer familiarises
himself with; the information contained within
the information pack that accompanies the
heater, the heater itself, and with the specific
requirements of the installation /application.
Warning
All Cabinet Heaters undergo a rigorous test
programme prior to being despatched, whilst
such a programme does involve pre-
commissioning and setting up the heater to
operate efficiently and well within its designed
operational limits, this does not mean that on
site commissioning is less important than
might otherwise be the case.
Note
It is strongly recommended that equipment
used for the sampling and analysis of flue
gases is accurate to within +/- 0.1% and
maintained so that it is regularly calibrated.
4.1 Commissioning - Pretest
Check to ensure electrical safety, and inspect
and check the installation, testing for leaks.
(a) Ensure that the electrical supply is turned
off.
(b) Ensure that the gas supply is turned off.
(c) Check that all panels and fasteners are
secure and in place.
(d) Check that the heater is installed so that it
is square and that the support is adequate.
(e) Ensure that warm air delivery outlets are
open and that ducting is adequately
supported.
(f) Ensure that if filter assemblies are fitted
that they are secure and correctly located.
(g) Check that air inlets are clear and that
return air paths are adequate.
(h) Ensure that the flue is secure, adequately
supported, and that the various joints are
properly sealed.
(i) Check that condensate trap and drain
facilities are adequate.
(j) Check that there is provision for flue gas
sampling and that this sample point can be
plugged and sealed after commissioning.

(k) Check that fan and limit stat settings have
not been disturbed and are as follows
100/700 800/1000
Range
Fan on - 60oC Fan on - 50oC
Overheat limit -100oC Overheat limit -100oC
Fan off - 30oC Fan off - 30oC
Also check that the white button (automatic)
is pulled outward and that the red button
(reset) is pushed inwards to the reset
position. See fig 15.
(l) Remove lower panel and check motor and
fan drive system for integrity of joints, check
pulley alignment, fan rotation, and belt
tension (see section 5.2 and figs 17 and 18).
(m) Ensure that the burner is securely
attached to the heater.
(n) Test for electrical earth continuity
between the heater, oil pipe work, and mains
supply.
ANALOGUE TYPE
(o) Turn on main electrical supply, select the
following switch settings
On/Standby - Standby
Heat/Ventilation - Ventilation
Manual/Automatic - Manual
OPTIMISED TYPE
Press FAN /Enter
The fan will start enabling fan direction etc to
be verified. Reset on/standby switch to
standby position
(p) Turn mains electrical supply to off,
replace and secure lower louvered panel
covering fan and motor assembly.
(q) Set room thermostat and time clock to
'demand' positions.
4.2 Commissioning - Ignition
Warning
Do not proceed with commissioning unless
all the criteria detailed within sections 4.0
and 4.1 have been satisfied.
(a) Ensure that the electrical supply is turned
off.
(b) Ensure that the gas supply is turned off.
(c) Select the following switch settings on the
heater
ANALOGUE TYPE
On/Standby - Standby
Heat/Ventilation - Heat
Manual/Automatic - Automatic
(d) Turn on main electrical supply.
(e) Select 'on' position for heater on/standby
switch.
OPTIMISED TYPE
(f) Prog 0000 Enter 1TEMP key in an
operating temp and Enter
Press RUN 3 times to return to main screen
Press OVER button Select 1 OVERIDE then
select 1 and key in 01 hour override this will
allow enough time to commission the heater
safely
(g) Check for the following burner sequence
Interval Operand
1 <5s Combustion air damper actuated,
burner fan motor initiates purge
cycle...
2 <40s Pilot valve opens ignition
transformer provides spark for
pilot ignition...
-------- E I T H E R --------
3 >40s Ignition failure caused by gas
starvation resulting in burner lock-
out/shut-down...
(g) Clear burner lockout using burner reset
function.
(h) Set heater on/standby switch to standby
position
(i) Open gas supply cocks Repeat steps 4.1
q, and 4.2 c,e,f.
----------- O R ----------
3 >40s Pilot ignition... Burner ignition...
4 <60s Burner ignition cycle complete