EXPO MiniPurge ZLC Series User manual

ML447 | v22
16-April-2020
MiniPurge Type Z(Y) LC
Manual
ML 447
This manual covers Mini-Z(Y)-Purge Leakage Compensation
Sizes: 1, 2 & 3
Mounting Options: bp, pm, nm, ss
Output Options: IS, PO
CONTENTS:
1. Specification Sheet –MiniPurge Type Z(Y) Systems
2. Application Suitability
3. Installation, Operation and Maintenance for LC Systems
4. Drawings
5. Certificates
6. D890 Appendix

ML447 | v22
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1. Specification Sheet –MiniPurge Type Z(Y) Systems
Supply Pressure : 60 psi / 0.4MPa / 4 barg must be regulated at inlet.
Maximum supply pressure 115 psi / 0.8MPa / 8 barg. Compressed Air / Nitrogen
Flow & Pressure Sensors
"Low Pressure Sensor" : 0.2 "WC / 50 Pa (0.5 mbarg)
"Flow Sensor" : 1.1 "WC / 280 Pa (2.8 mbarg)
Leakage Compensation : Size 1: Variable up to 2 scfm (60 Nl/min) to compensate for Enclosure Leakage
: Size 2: Variable up to 9 scfm (250 Nl/min) to compensate for Enclosure Leakage
: Size 3: Variable up to 28.3 scfm (800 Nl/min) to compensate for Enclosure Leakage
Relief Valve
MiniPurge Size 1 MiniPurge Size 2 MiniPurge Size 3
Model No RLV25/ss/FS RLV36/ss/FS RLV52/ss/FS
Opening Pressure : 4” WC / 1 kPa (10 mbarg)
Material : 316L Stainless Steel, Spark Arrestor: Stainless Steel mesh, Neoprene Gasket
Action on “Loss of Pressure” : ALARM ONLY
Size
1= Sub MiniPurge
Purge flow rate 8 scfm, 225 Nl / min
2= MiniPurge
Purge flow rate 16 scfm, 450 Nl /min
3 =Super MiniPurge
Purge flow rate 32 scfm, 900 Nl/min
Purge System Type
07 = MiniPurge
Approval / Certification
Z = Y =
Europe
EN 60079-0, EN 60079-2
Sira 01ATEX1295X
2813 II 3 (2) G D 2813 II 2 (2) G D
Ex [pzc] IIC T6 Gb Ex [pyb] IIC T6 Gb
Ex [pzc] IIIC T85ºC Ex [pyb] IIIC T85ºC Db
Tamb -20ºC +55ºC Tamb -20ºC +55ºC
IEC
IEC 60079-0, IEC 60079-2
IECEx SIR 07.0027X
Ex [pzc] IIC T6 Gb Ex [pyb] IIC T6 Gb
Ex [pzc] IIIC T85ºC Ex [pyb] IIIC T85ºC Db
Tamb -20ºC +55ºC Tamb -20ºC +55ºC
USA / Canada NFPA 496
FM 1X8A4AE
Class I Div 2 Class I Div 1
Groups A, B, C & D Groups A, B, C & D
Tamb = 60oC Tamb = 60oC
UL E190061
Class I Div 2 Class I Div 1
Groups A, B, C & D Groups A, B, C & D
Brazil
INMETRO - TUV
TÜV 12.1462X
Ex [pzc] IIC T6 Gb Ex [pyb] IIC T6 Gb
Ex [pzc] IIIC T85ºC Db Ex [pyb] IIIC T85ºC Db
-20ºC ≤Ta ≤+55ºC -20ºC ≤Ta ≤+55ºC
For limitations and conditions of use refer to the applicable certificate at the back of this manual.
Alarm (Signals)
IS = Internal Switch
‘Alarm’ : Dry, VFC, SPST N/O Contact
For Intrinsically Safe Circuits:
Install to EP80-2-11
Ci = 0 Li = 0
Umax = 30 Vdc, Imax = 101 mA
Umax = 19.2 Vdc, Imax = 350 Ma
Hermetically Sealed Switch (ATEX only)
Ex mc IIC T5 Gc
Ex mc IIIC T100ºC Dc
Vmax = 254 Vac, Imax = 0.7 A
PO = Pneumatic Output
‘Alarm’ : Loss of Pressure = No signal
”Pressurized” = at supply pressure
MiniPurge Housing
bp = Back Plate (Top/Side Mount) 316L
Stainless Steel (NROB finish)
pm = Panel Mount (Side/Front Mount) 316L
Stainless Steel (NROB finish)
nm = Non Metallic (Top/Side Mount)
Polystyrene c/w clear cover
ss = 316L Stainless Steel (NROB finish)
Neoprene “Top” Mount Gasket
Purging Method
LC= Leakage Compensation
Model No. (Example): 07 1 ZLC / ss / IS (Note: Not all codes are applicable)

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2. Application Suitability
MiniPurgeSystems are certified for use in Hazardous Areas, where the Hazardous Area is
non-mining (i.e. above ground) and the hazard is caused by flammable gasses, vapours or
dust.
Mini-Z-PurgeSystems may be used in IECEx, ATEX Zone 2(22) - Category 3 and NEC 500
Class I, Div 2.
Mini-Y-PurgeSystems may be used in IECEx, ATEX Zone 1(21) - Category 2 and NEC 500
Class I, Div 1.
MiniPurgesystems may be used for hazards of any gas group. However, apparatus
associated with the MiniPurgesystem, such as Non-Incendive, Intrinsically Safe signalling
circuits and flameproof enclosures containing switching devices may be limited in their gas
group. The certification documentation supplied with any such devices must be checked to
ensure their suitability.
This system is designed for use primarily with compressed air. Where other inert compressed
gasses are used (Nitrogen, for example) the user must take suitable precautions so that the
build up of the inert gas does not present a hazard to health. Consult the Control of
Substances Hazardous to Health (COSHH) data sheet for the gas used. Where a risk of
asphyxiation exists, a warning label must be fitted to the Pressurized Enclosure.
The following materials are used in the construction of MiniPurgesystems. If substances that
will adversely affect any of these materials are present in the surrounding environment, please
consult Expo for further guidance.
Materials of construction:
•Stainless Steel
•Aluminium
•Acrylic
•Mild (carbon) Steel
•Nylon
•Silicone Rubber
•Brass
•Polyurethane
•Neoprene

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E: [e-mail]
Expo Technologies US
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Expo Technologies China
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3. Installation, Operation and Maintenance for LC Systems
This MiniPurgeis designed for use under normal industrial conditions of ambient temperature,
humidity and vibration. Please consult Expo before installing this equipment in conditions that
may cause stresses beyond normal industrial conditions.
The MiniPurgesystem shall be installed and operated in accordance with relevant standards,
such as IEC / EN 60079-14, NEC 500, NFPA 496 and any local codes of practice that are in
force.
For IEC / ATEX applications, references to the NFPA 496 within the ML384, should be
replaced by the equivalent clause in IEC / EN 60079-2.
For IEC / ATEX applications, the "Example calculations:" in section 1.1.4 within ML384 should
read:
If the PE external dimensions indicate a volume of 500 Litres then,
500 litres enclosure volume x 5volume changes = 12 minutes purge time
225 litres/minute purge flow rate

Expo Technologies Limited Page 1 of 8 ML384 Issue 05 –04.06.15
Installation, Operation and Maintenance Manual for MiniPurge
Leakage Compensation (Model LC) and
MiniPurge Continuous Flow with High Purge (Model CFHP)
conforming to NFPA 496
IMPORTANT NOTE It is essential, to ensure conformity with the standard,
that the user of the system observes the following instructions.
Please refer to the latest standard for detailed requirements and definitions.
Contents:
Section 0 Description and Principle of Operation
Section 1 Installation of the System
Section 2 Operation of the System
Section 3 Maintenance of the System
Section 4 Fault Finding
Section 5 Annex (if applicable)
Section 0 Description and Principle of Operation
All MiniPurge pressurization systems provide:
a) a method of pressurizing a Pressurized Enclosure (PE)
while at the same time compensating for any leakage,
together with
b) a method of purging the enclosure, before power is
turned on, to remove any flammable gas that may have
entered the enclosure while it was not pressurized.
Type Leakage Compensation (LC) and Continuous
Flow with High Purge (CFHP) systems comprise the
following two major parts:
- A Control Unit (CU) containing as a minimum, for “Y”
and “Z” Pressurization, a Leakage Compensation Valve
(LCV), Minimum Pressure and Purge Flow sensing
devices, and a “Pressurized”/”Alarm” indicator. The CU
supplies a ‘Pressurized’ signal showing whether the PE
pressure is satisfactory or not.
For Type “X” Pressurization, the CU has, in addition, a fully
automatic Purging controller with a Purge timer and
electrical power switch interlock.
Note: For “Y” Pressurization, the electrical equipment
inside the protected enclosure shall meet the
requirement for Division 2 or Class 2 locations.
- A Relief Valve (RLV), fitted to the PE, to provide a
means of limiting the maximum pressure experienced by
the PE during operation. The RLV model number has
suffixes defining the diameter of the valve aperture (in
millimeters) and material, e.g. RLV **/cs (Carbon Steel) or
/ss (Stainless Steel). All RLVs incorporate a Spark Arrestor
to prevent sparks being ejected from the PE through the
RLV aperture.
CFHP systems with a Continuous Flow of air after purging
have a calibrated Outlet Orifice which can be either within
the Relief Valve (suffix **/cf) or a separate item type SA**
or SAU**.
0.1 “Leakage Compensation” Systems, Model LC
A Leakage Compensation System, Model LC, is intended
to have minimal flow after the initial purge time. The PE is
built as leak tight as possible and the LC system merely
tops up for any enclosure leakage. The system provides an
initial high flow of purging air that leaves the PE through
the Relief Valve. After the initial purging has been
completed the Control Unit changes over to Leakage
Compensation mode and the Relief Valve closes. The only
flow thereafter is the flow through the “Leakage
Compensation Valve” (LCV) which is adjusted so that
the flow is enough to compensate for any leakage from
the PE.
The Purging Flow rate is monitored by a separate
“Purge Flow Sensor” located in the CU, which detects
the differential pressure across the purge flow orifice
located directly before the RLV. The Purge Flow
Sensor is set to operate when the desired differential
pressure is exceeded. The output from the Flow
Sensor is indicated on the CU and on “X”
Pressurization systems, used to operate the automatic
purge timer. Both Enclosure Pressure and Purge Flow
have to be correct before the Purge Timer can start.
0.2 “Continuous Flow after High Purge”, Model
CFHP System
The CFHP system construction is identical to a LC
model, with the addition of one or more fixed Outlet
Orifices to provide a deliberate “leak” at a known flow
rate. The Outlet Orifice is pre-calibrated so that the
pressure drop at the desired flow rate is known. The
Minimum Pressure Sensor within the Control Unit will
be set to the same value as the pressure drop. When
the PE pressure exceeds the calibrated pressure the
Continuous Flow must be taking place.
The Leakage Compensation Valve in the CU is opened
sufficiently to provide enough air to compensate for
any accidental leakage as well as to provide the
Continuous Flow through the outlet orifice. In this way
a high flow rate is provided during the initial purge
period which is thereafter reduced to the desired
Continuous Flow rate. Even if the PE had no
accidental leakage there would still be a flow from the
outlet orifice.
There are three ways of providing the calibrated Outlet
Orifice. Please consult the system specification sheet
to determine which has been supplied. The choice:
- Type SAU** where an Orifice disk is removable and
can be easily changed by the user to give different flow
rates according to the size of the PE and the available
air supply capacity. (** denotes the metric thread size
of the SAU body)
- Type SA** where the orifice size is fixed and the way
to change the flow rate is either to change the setting

Expo Technologies Limited Page 2 of 8 ML384 Issue 05 –04.06.15
of the Minimum Pressure Sensor or to replace the SA with
one of another size. (** denotes the nominal thread size of
the SA body)
- For low flow rates, the Outlet Orifice may be
incorporated within the Relief Valve making use of the
existing Spark Arrestor. The Relief Valve will then have a
suffix /CF**, where ** is the orifice size in millimeters.
Section 1 Installation of the System
The installation of the MiniPurge system, the
protective gas supply, any alarm device should be in
accordance with the requirements of NFPA 496.
The electrical installation associated with the
MiniPurge system shall conform to the local codes
and the relevant clauses of NFPA 496.
All electrical parts of the MiniPurge system shall be
installed in accordance with the applicable
requirements of the NEC for USA and CEC for Canada.
1.1 Installation of the Expo LC and CFHP Systems
1.1.1 The Expo system should be installed either directly
on or as close as possible to the Pressurized Enclosure
(PE). It should be installed so that the system indicators
may be readily observed.
1.1.2 All parts of any system carry a common serial
number. If installing more than one system, ensure that
this commonality is maintained on each installation.
1.1.3 Any tubing, conduit and fittings used to connect to
the PE should be metallic, or, if non-metallic, conform to
the local codes for flammability ratings. No valve may be
fitted in any tube connecting the Expo system to the PE.
1.1.4 The user or manufacturer of the PE shall determine
the volume of the PE, the necessary purging volume, and
the time to be allowed for purging, using the chosen Expo
system purging flow rate. It is the user's responsibility to
verify or enter this data on the PE and/or Expo system
nameplate. Ask Expo if in doubt.
Example calculations:
a) If the PE external dimensions give a volume of 20 cubic
feet, and it is NOT a motor, multiply the volume by four to
get the Purging Volume i.e. 80 cubic feet. Divide the
Purging Volume by the purge rate e.g. 32 cubic feet per
minute, and round up to the next even minute above, i.e.
Purging time would be 4 minutes.
b) If the PE is a motor, multiply the internal free volume by
ten to get the Purging Volume. For the example above,
Purging time would be 8 minutes.
For Type “Y” or “Z” Pressurization, the protected
equipment may be permitted to be energized immediately
where 25 Pa (0.1”WC) exist in the enclosure and the
enclosure is known to be below the ignitable concentration
of combustible material.
1.1.5 If the PE contains an internal source of release of
flammable gas or vapor, the procedures for assessment of
the release as given in NFPA 496 shall be observed.
1.1.6 User must take precaution if abnormal release of
flammable gas or vapor within the enclosure can affect the
external area.
1.1.7 Where a release of flammable gas or vapor
within an enclosure can occur either in normal
condition or abnormal operation, protection shall be
provided by one of the step as specified in NFPA 496.
For more information on enclosure containing internal
source of release or enclosure containing an open
flame, contact Expo Technologies.
The user must verify that the specification of the Expo
system e.g. pressures, continuous flow (dilution) rate
and type of protective gas are correct for the specific
application. If an inert protective gas is required, the
Expo Control Unit can be specified to have
Compressed Air for the control logic and Inert Gas for
the protective gas to minimize Inert Gas consumption.
1.1.8 More than one PE can be protected by a single
system. If PEs are connected and purged in “series”
e.g. “Daisy Chained”, the Outlet Orifice must be fitted
on the last enclosure with the Purge Inlet to the first
enclosure. The bore and length of the tube or conduit
used to interconnect the enclosures is critical and will
determine the maximum pressure experienced by the
first enclosure in the series. Advice on sizing can be
obtained from Expo Technologies. The test pressure
for all the enclosures should be 3 times the pressure
inside the first enclosure when purging is taking place.
If PE’s are to be connected in parallel each enclosure
must have its own outlet Relief Valve, Purge Flow
Sensor and Pressure Sensor. System “Models” can be
mixed e.g. Model LC for one enclosure and Model CF
for another. An example would be a Gas
Chromatograph instrument. Expo systems with this
facility have option code “TW”.
1.2 Quality and Installation of the Pressurizing
Air or Inert Gas Supply
1.2.1 The source of the compressed air must be in a
non-classified area. Inert gas may be used as an
alternative to compressed air.
1.2.2 All pipe connection for the protective gas shall be
protected from mechanical damage; where the source
of the compressed air intake line passes through a
classified location, the construction shall be of non-
combustible material, and designed to prevent leakage
of flammable gases, vapours, or dust into the
protective gas. It must be protected against
mechanical damage and corrosion.
1.2.3 Unless a supply shut-off valve has been
specially fitted within the Expo system, a valve with the
same, or larger, thread size as the Control Unit inlet
fitting shall be fitted externally. In addition, for "Y" and
"Z" Pressurization systems, a suitable indicator shall
be provided:

Expo Technologies Limited Page 3 of 8 ML384 Issue 05 –04.06.15
Note: To conform to NFPA: Any protected enclosure that
can be isolated from the protective gas supply shall be
equipped with an alarm and shall have this warning:
WARNING: PROTECTIVE GAS SUPPLY VALVE
This valve must be kept open unless the area atmosphere
is known to be below the ignitable concentration of
combustible materials or unless all equipment within the
protected enclosure is de-energized.
1.2.4 The tubing and fittings used must conform to 1.1.3
above.
1.3 Provision and Installation of Alarm Devices
Expo Technologies systems have a Minimum Pressure
Sensor set to a pressure of at least 0.1” WC (0.25 mbar).
When the PE pressure is above this set point the Sensor
produces a positive "Pressurized" signal. This is displayed
on a Red/Green indicator. This signal can be used to
operate an electrical contact for a remote “Alarm”. The
pneumatic signal may be supplied either
a) to a pressure operated switch (MiniPurge Option Code
/IS) suitable for an Intrinsically Safe circuit, in accordance
with Expo drawing EP80-2-11, (or for a Non-Incendive
circuit in Division 2), or
b) to a bulkhead fitting where it is available to the user
(MiniPurge Option Code /PO). This signal can be used to
operate an external electrical switch either local (e.g.
explosionproof) or remote in a non-classified area, or
c) to an external terminal box (MiniPurge Option Code
/PN). This option is available with an auxiliary switch(es)
for signal and circuit control, assessable to user via the
external junction box. This switch is suitable for use in the
Hazardous Location in accordance to NEC500/505
requirements.
When the enclosure pressure falls below the set point of
the Sensor the "Pressurized" signal is removed, i.e. the
absence of the signal indicates a “Alarm” ("Pressure
Failure") condition. The user must make use of this
external alarm facility in accordance with NFPA 496
requirements, if the system “Alarm” indicator is not located
in a place where it can be readily observed.
Example: The "Pressurized" signal can be used to produce
an "Alarm" action by means of a conventional "pressure
switch" set to operate at around 15 psi (1 bar). The
"Pressurized" signal from the CU at 30 psi (2 bar) or more
will hold the switch in the operated position until the CU
detects a low pressure in the PE and removes the
"Pressurized" signal. The Alarm switch will reset and its
contacts can be used to operate a remote electrical alarm.
If the switch is located in the hazardous area it must either
be part of an Intrinsically Safe circuit, or be suitably
protected e.g. explosionproof. The pressure switch should
be IS or explosionproof even if it is fitted within the
Pressurized Enclosure.
For
Expo Technologies Tip: Exception: For a “Z Purge”
system fitted in a Division 2 area, a non-classified
switch inside the PE can be used to operate a remote
Alarm provided its electrical supply comes from within
the PE (i.e. NOT PROVIDING DRY CONTACTS).
When the PE is in use the Alarm can operate
normally in response to the pneumatic signal from
the CU with option /PO. When the PE power is
switched off there is no need for an alarm! Ask for
the circuit diagram.
The Alarm switch can also be located in a nearby non-
classified location. To get the best response time the
switch should be as close as possible to the CU and the
maximum length of tubing between the CU and the Alarm
switch should not exceed 150 feet (45 m) unless “Quick
Exhaust Valves” are used (please ask Expo if in doubt).
Note: No valves may be fitted between the Expo
system and the alarm switch.
1.4 Power Supplies and their Isolation
1.4.1 All power entering the PE shall be provided with
a means of isolation. This requirement also applies to
any external power sources that are connected to "dry
contacts" or "volt-free contacts" within the PE.
1.4.2 Electrical power for the protective gas supply
shall be from a separate power source. If the same
power source for the pressurized enclosure is used, it
shall be power off before any service disconnects for
the enclosure.
Exception: Power to Intrinsically Safe, or other
apparatus, which is already suitable for the location,
need not be isolated by the Expo Technologies
system.
Expo Technologies Tip: It is recommended to fit
dry or volt-free contacts in the non-classified area
or inside an explosionproof box rather than inside
the PE. Please ask Expo about “MiniPurge
Interface Units” (MIU).
In the case of "X" Pressurization, the isolation of the
power must be controlled by the Expo system using
the "Purge Complete" pneumatic signal to operate a
"Power Switch" in a similar manner to that described in
1.3 above.
In the case of "Y" or "Z" Pressurization the power may
be controlled manually by the user by the use of local
isolating switch.
1.4.3 In accordance with NFPA 496, Mini-X-Purge
system shall be used on protected equipment requiring
automatic shutdown, such as motors or transformers
that could be overloaded or equipment that can
develop higher temperature than the marked
Temperature Class (temperature detector devices shall
be provided to detect any increase in temperature).
Expo Mini-X-Purge systems can have the "Action on
Pressure Failure" (normally "Alarm and Trip") adjusted
by the user to become "Alarm Only". In case of an
alarm, it is the responsibility of the user to de-energize
the protected equipment as soon as possible. The
system may require the addition of an “Alarm Only Kit”
(/AO) to perform this function. Please contact Expo
Technologies Sales office for further details.
Exception: The power may remain connected for a
short period if immediate cut-off could result in a more

Expo Technologies Limited Page 4 of 8 ML384 Issue 05 –04.06.15
hazardous condition and if audible and visual alarms are
provided in a constantly attended location.
1.4.4 The Power (cut-off) Switch must be approved for the
location or located in a non-classified area.
1.4.5 No valves are permitted between the Power Switch
and the Expo system.
1.4.6 For "X" Pressurization, the PE door shall have
fasteners that can be opened only by the use of a tool or
key. Otherwise the additional requirements from NFPA 496
should apply.
1.4.7 Protection equipment containing hot parts requiring a
cool-down period shall require the use of key or tool for
opening.
Note: The door switch provided with the Expo system
(when requested) can be either pneumatic or electric.
1.5 Marking
1.5.1 The MiniPurge system carries a nameplate and a
specification sheet, which give specific data such as serial
and models numbers, Pressure Sensor settings, flow rates
and purge time.
1.5.2 Other marking, for the PE, required by the
standard includes:
“WARNING - PRESSURIZED ENCLOSURE
This enclosure shall not be opened unless the
area is known to be free of flammable materials or
unless all devices within have been de-energized"
"Power shall not be restored after the enclosure
has been opened until the enclosure has been
purged for____minutes at a flow rate of_____."
Expo note: It is understood that NFPA 496 requires the
de-energization of all devices that are not suitable for
the hazard e.g. devices that are not Explosionproof or
Intrinsically Safe. For example, an explosionproof anti-
condensation heater would not have to be de-
energized.
1.5.3 If Inert Gas is used as the Protective Gas and a
risk of asphyxiation exists, a suitable warning plate
should be fitted to the PE.
Section 2 Operation of the System
2.1 Initial Commissioning
2.1.1 Check that the system has been installed in
accordance with Section 1 of this manual.
2.1.2 Disconnect the supply pipe from the inlet to the
Control Unit and blow clean air through for at least 5
seconds per foot of length (15 sec / metre) to remove any
debris, oil and condensation.
2.1.3 Connect a temporary pressure gauge or liquid
manometer to the PE or Control Unit “Pressure Test Point”,
[on the LP Sensor, by the removal of the Red plug - 5/32”
(4mm) OD nylon tube].
2.2 Commissioning Leakage Compensation (LC) and
Continuous Flow High Purge (CFHP) ”X” Purge
systems.
On LC and CFHP "X" Purge systems proceed as follows:
2.2.1 Open the Leakage Compensation Valve (LCV) to
about 50% of its travel.
2.2.2 Open the supply shutoff valve SLOWLY and allow
the PE pressure to rise until the Relief Valve (RLV) opens.
Check that the RLV opens at or below the figure specified
in the documentation. Repeat the test several times.
2.2.3 Open the supply shutoff valve fully and the purging
flow will start.
2.2.4 Check that the internal logic gauge reads 30 psi (2
bar). If not, adjust the logic pressure regulator to suit (lift
the red ring to unlock the knob first.)
2.2.5 At this time the “Pressurized” indicator should be
Green and the “Purging” indicator should be Yellow. If the
"Purging" indicator remains Black the flow through the
Relief Valve is below the minimum for which the Flow
Sensor has been calibrated. Check the air supply pressure
at the inlet to the Control Unit while purging is taking
place. It must be above the minimum specified. The
larger Super-Mini-X-Purge system has a built-in
gauge on the filter for this purpose.
2.2.6 On LC and CFHP "X" purge systems the purge
timer will start as soon as the “Purging” indicator turns
Yellow. Check that the time delay between the
indicator turning Yellow and the application of power to
the PE is not less than the minimum time required to
purge the PE. Times in excess of the minimum are
permitted and a tolerance of +25% is normally
acceptable. If the time is too short it must be adjusted
accordingly.
The system uses a pneumatic incremental timer which
is adjusted by fully opening or closing one or more of
five screwdriver-operated valves, arranged in a block
on the control logic manifold – see GA Drawing. The
opening of each valve incrementally provides a fixed
number of minutes of purging time as in the following
table
Valve: 1 2 3 4 5
Minutes: 2 4 8 8 16
Thus for a 12-minute purge time, valves 2 and 3 would
be open and the others closed. For twenty-four
minutes, 4 and 5 would be open and the others closed.
At least one valve must always be open and the
screws must be at the appropriate limit of travel.
2.2.7 After the power has been turned on by the
Control Unit, the Purging Valve will close and the air
flow into the enclosure will be controlled by the
Leakage Compensation Valve (LCV). The initial setting
of 50% open may be too high or too low. It should now
be adjusted to set the PE pressure and leakage.
There are three possible situations:

Expo Technologies Limited Page 5 of 8 ML384 Issue 05 –04.06.15
a) Air continues to come out through the RLV Spark
Arrestor after power has been turned on in considerable
quantity. The LCV is too far open and the air flow is holding
the RLV open continuously. (Note: Some CFHP systems
have a deliberate but modest “Continuous” air flow through
the RLV in normal operation; do not confuse this flow rate
with that caused by excessive setting of the LCV.) Close
the LCV slowly observing the manometer or gauge (see
item 2.1.3 above). The PE pressure will start to fall as the
flow decreases but eventually the RLV will close and the
pressure rise again. At this point the Relief Valve may start
to open intermittently as the PE pressure rises to the point
where the RLV re-closes and the enclosure pressure starts
to rise again. This is entirely normal for this type of RLV.
Proceed now to b) below:
b) If the Relief Valve is opening intermittently the LCV is
slightly too far open. Observe the manometer or gauge.
When the RLV opens the enclosure pressure falls quickly
to the point where the RLV recloses and the enclosure
pressure starts to rise again. This is entirely normal for this
type of RLV and shows that it is working correctly.
Then continue to close the LCV until the cycling stops and
the enclosure pressure starts to fall. Carefully adjust the
LCV until the PE pressure is approximately 50% of the
RLV opening pressure and stable. This pressure may be
around 2” WC (5 mbar) and will be the “normal working
pressure”.
We recommend that the setting of the Minimum Pressure
Sensor is checked at this time. Note the position of the
LCV knob. Slowly lower the PE pressure by closing the
LCV further counting the number of turns from the “normal
working pressure” position. Note the pressure at which the
“Pressurized” indicator turns Red and check that it is not
lower than the figure given in the documentation. Check
also the “Alarm” electrical contacts (if fitted).
As soon as the “Pressurized” indicator turns Red, the
enclosure power will be switched off (see also 2.2.8 below)
and the system will start to re-purge.
While it is re-purging return the LCV to its “Normal Working
Pressure” position so that, at the end of purging the
enclosure pressure should immediately settle down at the
correct “normal” pressure. Finally re-adjust the LCV if
necessary.
c) If, at the end of purging, the PE pressure falls below the
Minimum Pressure Sensor setting the LCV is not open far
enough. The system will start to purge again. While it is
purging open the LCV fully and check the enclosure for
leakage. This time, at the end of purging, the enclosure
should stay pressurized and the Relief Valve action be as
in a) or b) above. It is likely that there is significant leakage
from the enclosure and attempts to reduce the leakage will
be time well spent.
CFHP systems are intended to have a Continuous Flow
through the enclosure. The Continuous Flow may emerge
through the RLV, in which case the RLV will have a “CF” in
its model number. Some CFHP systems will have a
separate Outlet Orifice/Spark Arrestor and air can be felt
emerging through this aperture whenever the enclosure is
pressurized.
2.3 Commissioning Leakage Compensation (LC)
and Continuous Flow/High Purge (CFHP) “Y” and
“Z” Systems.
On LC and CFHP “Y” and “Z” Purge systems, proceed
as follows:
2.3.1 Open the supply shutoff valve.
2.3.2 Adjust the Leakage Compensation Valve (LCV)
so that the enclosure pressure rises to the point where
the “Pressurized” indicator turns green.
2.3.3 Continue to raise the PE pressure until the
Relief Valve (RLV) opens. Check that the RLV opens
at or below the figure specified in the documentation.
Repeat the test several times.
2.3.4 Lower the PE pressure until the “Pressuized”
indicator turns Red. Check that the indicator turns Red
at or above the pressure specified in the
documentation. Check the external alarm contacts (if
fitted).
2.3.5 Open the LCV again and set the PE pressure to
a level around 50% of the RLV operating pressures.
This “working” pressure is not critical. The
“Pressurized” indicator should be Green.
2.3.6 Turn the Purge Control Valve “On”. This will start
the High Purge Flow and the “Purging” indicator should
turn Yellow. If the “Purging” indicator remains Black the
flow through the outlet valve is below the minimum for
which the Flow Sensor has been calibrated. Check the
air supply pressure at the inlet to the Control Unit while
purging is taking place. It must be above the minimum
specified. (Super-Mini-Purge systems have a built-in
gauge on the filter for this purpose.) If the supply
pressure is correct and the “Purging” indicator does not
turn Yellow, there is too much leakage from the
Pressurized Enclosure. Find and fix the leaks!
“Purging” does not start until the indicator turns
Yellow
2.3.7 On LC and CFHP “Z” Purge systems the purge
timing function is performed by the user. When the
“Purging” indicator turns Yellow the Purge Flow is
above the minimum required and the purge time can
start. The user must ensure that the time delay
between the indicator turning Yellow and the
application of power to the PE is not less than the
minimum time required to purge the PE as shown on
the PE or Expo system nameplate.
Never turn on the power without purging first
unless you have proved that the interior of the PE
is gas free and checked that the “Pressurized”
indicator is green!
2.3.8 After the purge time is completed the Purging
Valve should be turned “Off”. The High Purge Flow will
cease and the air flow into the enclosure will then be
controlled once again by the Leakage Compensation
Valve (LCV), it should now be re-adjusted if necessary.
The RLV should be closed and the enclosure pressure
around 50% of the RLV opening pressure. If this is not
so there are three possible situations:
a) Air continues to come out through the Spark
Arrestor, after High Purge has been turned “Off”, in

Expo Technologies Limited Page 6 of 8 ML384 Issue 05 –04.06.15
considerable quantity. The LCV is too far open and the air
flow is holding the RLV open continuously. (Note: Some
CFHP systems have a deliberate but modest “Continuous”
air flow through the RLV in normal operation; do not
confuse this flow rate with that caused by the excessive
opening of the LCV.) Close the LCV slowly observing the
manometer or gauge (see item 2.1.3 above). The PE
pressure will start to fall as the flow decreases but
eventually the RLV will close and the pressure rise again.
At this point the Relief Valve will start to open intermittently
as the PE pressure rises to the point where it exceeds the
RLV opening pressure. When the RLV opens the pressure
will fall quickly to the point where the RLV re-closes and
the enclosure pressure starts to rise again. This is entirely
normal for this type of RLV. Proceed now to b) below:
b) If the Relief Valve is opening intermittently the LCV is
slightly too far open. Observe the manometer or gauge.
When the RLV opens the enclosure pressure falls quickly
to the point where the RLV re-closes and the enclosure
pressure starts to rise again. This is entirely normal for this
type of RLV and shows that it is working correctly.
Continue to close the LCV until the cycling stops and the
enclosure pressure starts to fall. Carefully adjust the LCV until
the PE pressure is approximately 50% of the RLV opening
pressure and stable. This pressure may be around 2”WC (5
mbar) and will be the “normal working pressure”.
c) If, at the end of purging, the PE pressure falls below the
Minimum Pressure Sensor setting the LCV is not open far
enough. The LCV should be opened until the PE
pressure is around the normal working pressure.
2.3.9 CFHP systems are intended to have a
Continuous Flow through the enclosure. The
Continuous Flow may emerge through the RLV, in
which case the RLV will have a “CF” in its model
number. Some CFHP systems will have a separate
Outlet Orifice/Spark Arrestor and air can be felt
emerging through this aperture whenever the
enclosure is pressurized.
2.3.10 “Y” and “Z” purge systems do not control the
enclosure power. It is the responsibility of the user to
switch off the power whenever the enclosure pressure
falls below the minimum permitted i.e. when the
“Pressurized” indicator turns Red.
2.4 Normal Operation
2.4.1 “X” Purge systems: Turn the air supply valve On
or Off to start or stop the system, After this the
Pressurizing and Purging sequence is entirely
automatic.
2.4.2 “Y” and “Z” Purge systems are started and
stopped in the same way as “X” purge system but the
user must close the Power Switch only after the
enclosure has been pressurized and purged sufficiently
to ensure that the interior of the enclosure is gas free. It
is the user’s responsibility to shut off the power, as soon
as possible after a pressure failure.

Expo Technologies Limited Page 7 of 8 ML384 Issue 05 –04.06.15
Section 3 Maintenance of the System
The maintenance recommended for the system consists of
the following, supplemented by any additional local
requirements imposed by the authority having jurisdiction.
3.1 Initial Maintenance
Expo recommends that the commissioning test be
repeated at least every six months. They include checking
the opening pressure of the Relief Valve, setting of the
Minimum Pressure Sensor, the "Normal Working Pressure"
of the enclosure and, for "X" Purge systems, the setting of
the purge timer (as described in Section 2 of this manual).
In addition, the following checks are also recommended at
that time:
- Check the RLV and any other Spark Arrestors. Remove
any debris or corrosion, or replace the Spark Arrestor with
a spare.
- Check the condition of the air supply filter element.
Clean or replace it as necessary.
3.2 Routine Maintenance
At least every two years, the following additional
checks are recommended:
- Apparatus is suitable for the Hazardous Location
- There are no unauthorized modifications
- The source of air is uncontaminated
- The interlocks and alarms function correctly
- Approval labels are legible and undamaged
- Adequate spares are carried
- The action on pressure failure is correct
Section 4 Fault Finding – LC and CFHP Systems
4.1 General
If the system does not behave in the manner described
above there is a fault. Some of the more likely faults are
dealt with below. If a cure cannot be effected by following
the procedure shown below please call Expo (24 hour
answering) or your supplier for further assistance.
The system has been designed for ease of fault finding
and many of the components fitted are plug-in or sub-base
mounted. Check components by substitution only after
establishing that such action is necessary. If the system is
less than 12 months old, parts under warranty should be
returned to Expo Technologies for investigation, with a full
report of the fault and the system Serial number.
NOTE: As with any pneumatic system the greatest
enemies are water, oil and debris in the air supply. For this
reason a dust and water filter should always be fitted. But
debris can enter from other sources and it is vital therefore
that the procedures described in Section 2 is carried out
before using the system for the first time, or following any
disconnection of the pipework. Failure to perform this work
may cause damage, which will not be covered under
warranty.
Fault Finding
NOTE: Before making the following checks verify that the
main supply pressure is between 60 and 115 psi (4-8 bar)
at the Control Unit and, for X-Purge systems, the regulated
pressure on the logic gauge is 30 psi (2 bar)
4.2 Minimum Pressure Alarm is ON Continuously
(“Pressurized” Indicator is Red)
Possible cause 1: The Pressurized Enclosure (PE)
pressure is too low. Try increasing the setting of the
Leakage Compensation Valve (LCV) to raise the pressure
in the PE.
Possible cause 2: Enclosure fault?
- Is the ACTUAL PE pressure below the setting of
the Minimum Pressure Sensor? Check it with a
manometer or gauge.
- Is there debris stuck on the face of the Relief Valve
disk, perhaps held there because of the magnetic
material?
- Has the PE door been closed and all conduit/cable
glands sealed?
- Is the PE leaking too much?
- Has the pressure sensing tube been damaged?
Possible cause 3: System fault?
If checks above reveal that the PE is correct, the fault
probably lies in the Control Unit. The basic operation of
the Minimum Pressure Sensor can be checked by
unscrewing the 2.4” (60mm) diameter diaphragm and,
by using a finger, block the threaded hole in the top of
the valve module. The valve should operate and the
indicator should turn Green. If this works correctly and
the enclosure pressure is above the setting of the
Minimum Pressure Sensor it is likely that the Pressure
Sensor diaphragm needs re-calibrating or replacing.
(See 4.6)
4.3 Relief Valve Opens (Continuously or
Intermittently)
Possible cause 1: The PE pressure is too high.
The Leakage Compensation Valve (LCV) is too far
open. Adjust the LCV as described in Section 2 above.
Possible cause 2: Debris on the RLV disk allowing air
to leak from the valve. Remove the RLV cover and
clean the valve disk. The disk and spring may be
removed from the RLV without affecting the calibration.
4.4 “Purging” Indicator Will Not Turn Yellow
During Purging

Expo Technologies Limited Page 8 of 8 ML384 Issue 05 –04.06.15
Possible cause 1: Insufficient purging Flow due to
inadequate air supply pressure. Check the air supply
pressure at the inlet to the CU when flow is taking place.
Excessive pressure drop in the supply pipe is a very
common cause of this problem. The supply pipe must be at
least as big as the CU inlet fitting, i.e. at least ½” NB (12
mm). Super-MiniPurge systems with ¾” or 1” connections
must have AT LEAST this internal diameter for supply and
outlet tubing. Due to the high flows demanded from these
large systems the need for adequate supply tubing is
VITAL. If in doubt, or for long distances, install tubing that
is at least 50% larger than the inlet size!
Possible cause 2: Excessive Pressurized Enclosure (PE)
leakage. Check around the PE when flow is taking place.
Any significant leakage must be cured. Has a Leakage
Test been done? The total leakage should not exceed 10%
of the Purge Flow Sensor setting. Check for leakage down
the conduit through unsealed stopping boxes.
Possible cause 3: PE not strong enough. Repeat the PE
pressure test. Is is recommended that the PE is tested to
three times the Relief Valve opening pressure e.g. 12”WC
(30 mbar) for systems with default settings. Has this been
done?
Possible cause 4: The tubing from the RLV Flow Sensing
point to the Purge Flow Sensor is not air-tight e.g. fitting
nuts not tightened or tube damaged. Check and repair as
necessary.
Possible cause 5: The Purge Flow Sensor is not operating
correctly or out of calibration. The basic operation of the
Purge Flow Sensor can be checked by unscrewing the 2.4”
(60 mm) diameter diaphragm and by using a finger, block
the threaded hole in the top of the valve module. The valve
should operate and the indicator turn Yellow. If this works
correctly and the flow through the Relief Valve is above the
minimum required WITH THE RELIEF VALVE COVER
FIRMLY SECURED IN PLACE the Sensor diaphragm
needs re-calibrating or replacing.
4.5 System Fails to Switch Power On after the Purge
Time has Elapsed? (“X”-Purge Systems Only)
Possible cause 1: Is power available? Is the power
disconnect closed? Are the fuses or circuit breaker OK?
Possible cause 2: System fault? Timer not timed out?
a) Has the “Purging” indicator been Yellow for the whole of
the purge time?
b) Is the logic pressure gauge at 30 psi (2 bar) 10%.
c) Is there pressure at the Power Switch output bulkhead
and at the Power Switch itself? Is the Switch set at 15 psi
(1 bar)?
d) Is the pipe to the Power Switch airtight? The signal
to the Power Switch bulkhead has a restrictor that
limits the permissible leakage from the pipe.
e) Note the timer setting. Reset the timer to the
minimum available purging period (see 2.2.6) and
check operation on that purge time. If it works OK,
increase the time progressively until either it is correct,
or the system ceases to time out at all. In the latter
case, there is an air leak in the timer circuit. (A leak in
the timing circuit can cause the timer not to time out.) If
possible, establish the source of the leak with soapy
water and retest the system. This will involve removing
the chassis from the Control Unit –be sure this is the
cause before starting the work. It is VERY unusual!!
Ensure that the timer is returned to its original
setting and the purge time checked before putting
the system back into service.
Possible cause 3: Power Switch Fault. Check the
operation of the Power Switch. It should close above 20 psi
(1.4 bar).
4.6 Pressure Sensor Calibration
If it is decided that the Minimum Pressure Sensor or
Purge Flow Sensor needs re-calibrating it can either be
returned to Expo for this service or it can be done by
the user as follows:
Disconnect the pressure sensing pipe from the top of
the diaphragm. (It is a “push-in” quick release fitting;
firmly push inwards the collar surrounding the pipe
where it enters the fitting, and then pull the pipe
outwards while maintaining the pressure on the collar).
Unscrew the 2.4” (60 mm) diameter diaphragm
housing from the top of the Sensor. Invert it and note
the brass adjusting screw in the center. Turning the
screw inwards (clockwise) will lower the setting. It is
likely that the screw will be very stiff due to the locking
sealant. If the screw cannot be moved the application
of gentle heat in the area of the brass screw can often
help. DO NOT OVERHEAT!
4.7 Filter Cleaning
If the filter element needs cleaning the transparent
bowl can be unscrewed and removed. The filter
element also unscrews and can then be cleaned in
soapy water. Do not use solvents on any part of the
filter assembly.
Expo Technologies tip: It is sometime easier, if the bowl
is very tight, to remove the filter by undoing the fitting
that holds the filter into the Control Unit. On Sub-Mini-X-
Purge systems it may be necessary to remove the
Minimum Pressure Sensor diaphragm first.
Section 5 Annex of Options fitted
Refer to the annex of this manual for any options fitted as designated by the model code of the system
Expo Technologies Ltd Expo Technologies Inc,
Unit 2 The Summit, 9140 Ravenna Road Unit #3,
Hanworth Road, Twinsburg,
Sunbury-On-Thames, OH 44087,
TW16 5DB. UK. U.S.A.

ML447 | v22
Expo Technologies UK
T: [phone]
E: [e-mail]
Expo Technologies US
T: [phone]
E:[e-mail]
Expo Technologies China
T: [phone]
E: [e-mail]
4. Drawings
Consult the appropriate drawings according to the selected system.
SYSTEM *ZLC
/bp/IS
/bp/PO
/pm/IS
/pm/PO
/nm/IS
/ss/IS
/ss/PO
XBR-8TD0-011
✓
✓
XBR-7TD0-030
✓
✓
XBR-8TD0-009
✓
✓
XBR-7TD0-029
✓
✓
XBR-7TD0-031
✓
XBR-8TD0-013
✓
✓
XBR-7TD0-028 (1 & 2)
✓
✓
XBR-7TD0-032
✓
✓
✓
✓
✓
✓
✓
EP80-2-11
✓
✓
✓
✓
XSD-RTD0-004 (1 & 2)
✓
✓
✓
✓
✓
✓
✓
5. Certificates
For certificates refer to ML569
6. D890 Appendix

FLATNESS TO BE LESS THAN 0.4mm OVER ANY 100mm LENGTH
UNSPECIFIED
TOLERANCES
MATERIAL
DR'WN
APP'D
CHK'D
DRAWING STATUS:
APPROVED: MOD. No: DATE: ISSUE:
3rd ANGLE
PROJECTION
DIMENSIONS IN mm
DO NOT SCALE
Expo Technologies Limited
JOB No:
FINISH
TITLE
CUSTOMER: SHEET No. OF
SURREY TW16 5DB
UNITED KINGDOM
DRAWING No. SCALE
The contents of this drawing / document are Copyright ã Expo Technologies Limited. They are to be treated as confidential and are returnable
upon request. They are not to be copied or communicated in part or in whole without written consent from Expo Technologies Limited, neither
are they to be used in any way against our interests.
NO DEC PLACE ±0.5
1 DEC PLACE ±0.2
2 DEC PLACE ±0.1
PRESSURIZED
ENCLOSURE
RELIEF
VALVE
* CONTROL UNIT
Quick Installation Guide FOR LC:
With aid of supplied mounting template cut
mounting holes into the enclosure.Ensure
Control unit and Relief Valve are diagonally
opposing.
Fix MiniPurge Control Unit to enclosure. Fix Relief Valve to enclosure. Pipe between MiniPurge Control Unit & Relief
Valve.
Connect Output option, /IS or /PO as required,
refer to manual.
Connect isolated air supply to MiniPurge Control
Unit
Ensure enclosure door is closed and sealed from
leaks.
Turn on air supply 60 psig (4 barg).
Slowly increase Leakage Compensation Valve
until Alarm Indicator turns from RED to GREEN.
Turn Purge Control Valve to ON and ensure Purge
Indicator turns from BLACK to YELLOW.
After Purge time has been completed turn Purge
Control Valve OFF.
Power can now be applied to enclosure.
All queries refer to manual for assistance in the
first instance.
/PO option shown
10. 11. 12. 13.
9.
8.
7.
6.
3.
5.
4.
2.
1.
*
PURGE CONTROL VALVE
LEAKAGE COMPENSATION VALVE

FLATNESS TO BE LESS THAN 0.4mm OVER ANY 100mm LENGTH
UNSPECIFIED
TOLERANCES
MATERIAL
DR'WN
APP'D
CHK'D
DRAWING STATUS:
APPROVED: MOD. No: DATE: ISSUE:
3rd ANGLE
PROJECTION
DIMENSIONS IN mm
DO NOT SCALE
Expo Technologies Limited
JOB No:
FINISH
TITLE
CUSTOMER: SHEET No. OF
SURREY KT7 0RH
UNITED KINGDOM
DRAWING No. SCALE
The contents of this drawing / document are Copyright ã Expo Technologies Limited. They are to be treated as confidential and are returnable
upon request. They are not to be copied or communicated in part or in whole without written consent from Expo Technologies Limited, neither
are they to be used in any way against our interests.
NO DEC PLACE ±0.5
1 DEC PLACE ±0.2
2 DEC PLACE ±0.1
PURGE AIR
INLET
1/2" NPT(F)
= 160 [6.3"] =
200 [7.9"]
= 235 [9.3"] =
= 120 [4.7"] =
LEAKAGE COMPENSATION
VALVE
PURGE
CONTROL
VALVE
= 255 [10.0"] =
IN 6 POSITIONS:
M6 NUTSERT IN ENCLOSURE
Ø7.5 [0.3"] HOLE IN
MINIPURGE PANEL
REAR AND SIDE
VIEWS - IS OPTION
REAR AND SIDE
VIEWS - PO OPTION
= 180 [7.1"] =
275 [10.8"]
PURGING
INDICATOR
ALARM/PRESSURIZED
INDICATOR
ATMOSPHERIC
REFERENCE POINT
CERTIFICATION LABEL
EXPO LOGO
PURGE OUTLET
3/8" NPT (F)
LOW PRESSURE SENSOR
FLOW SENSOR
Ex nA-NI OR
I.S. ALARM SWITCH
LEAKAGE COMPENSATION
VALVE
FRONT VIEW PO AND IS OPTIONS
PURGE OUTLET
3/8" NPT (F)
LEAKAGE COMPENSATION
VALVE
PNEUMATIC ALARM/
PRESSURIZED OUTPUT AT
SUPPLY PRESSURE
1/8" NPT(F)
LOW PRESSURE SENSOR
FLOW SENSOR
GASKET GASKET

ON
OFF
FLATNESS TO BE LESS THAN 0.4mm OVER ANY 100mm LENGTH
UNSPECIFIED TOLERANCES
MATERIAL
DRAWING STATUS:
APPROVED: MOD. No: DATE: ISSUE:
3rd ANGLE
PROJECTION
DIMENSIONS IN mm
DO NOT SCALE
Expo Technologies Limited
JOB No:
FINISH TITLE
CUSTOMER:
SHEET No.
OF
SURREY KT7 0RH UNITED KINGDOM
DRAWING No. SCALE
The contents of this drawing / document are Copyright Expo Technologies Limited. They are to be treated as confidential and are returnable
upon request. They are not to be copied or communicated in part or in whole without written consent from Expo Technologies Limited, neither
are they to be used in any way against our interests.
NO DEC PLACE ±0.5
1 DEC PLACE ±0.2
2 DEC PLACE ±0.1
ALARM/PRESSURIZED INDICATOR
PURGE AIR INLET 1/2" NPT(F)
SYSTEM BREATHER -
DO NOT OBSTRUCT
180 [7.1"]103 [4.1"]
182 [7.2"]
208 [8.2"]
LEAKAGE COMPENSATION VALVE
31 [1.2"]
59 [2.3"]
96 [3.8"]
36
[1.4"]
58 [2.3"]
60 [2.4"]
= 110 [4.3"] =
16.5 [0.6"]
37 [1.5"]
35 [1.4"]
PURGE CONTROL VALVE
165 [6.5"]
167 [6.6"]
4 HOLES Ø5
FOR REAR MOUNTING
= =
PRESSURE FLOW SENSORS
INTERNAL VIEW IS AND PO OPTIONS
GASKET (NOT SHOWN) APPROX 2mm
THICK FITTED TO THIS SURFACE
87 [3.4"]
NOTES: MINI-Z-PURGE/ MINI-Y-PURGE MUST BE MOUNTED IN ONE OF THE
TWO ATTITUDES SHOWN. TOP / REAR MOUNT.
APPROX WEIGHT: 3Kg (6.6 POUNDS).
EACH SYSTEM IS SUPPLIED WITH TWO ORIFICE RESTRICT0RS TO
SUIT REQUIRED FLOW RATES.
IS OPTION SHOWN IN BROKEN LINE ( ).
1.
2. 3.
4.
212 [8.3"]
ALARM/ PRESSURIZED SIGNAL
OUTPUT AT SUPPLY PRESSURE
1/8"NPT(F)
5 OFF M4 MOUNTING HOLES
SCREWS & SEALOC WASHERS SUPPLIED
Ex nA-NI OR I.S. ALARM SWITCH
CONNECTED TO ALARM/
PRESSURIZED SIGNAL OUTPUT (IS
OPTION ONLY)
PURGING INDICATOR
FLOW SENSING
1/8" NPT(F)
ENCLOSURE PRESSURE
1/8" NPT(F)
PURGE OUTLET
1/2" NPT(F)