EXPO MiniPurge D801/ET User manual

ML488 | v18
22-Feb-18
D801/ET MiniPurge

Manual
ML 488
IMPORTANT NOTE
It is essential for safety that the installer and user of the Expo system observe the following instructions:
Please refer to the standard for principles and definitions.
(N.B. These instructions apply only to the Pressurizing system. It is the responsibility of the manufacturer
of the Pressurized Motor Enclosure to provide appropriate instructions for the Enclosure.)
Contents
1. D801 MiniPurge- General System Specification
2. Quick User Guide
3. Application Suitability
4. Description and Principle of Operation
5. Main Components
6. Installation of the System
7. Commissioning
8. Maintenance of the System
9. Fault Finding
10. Recommended Spares List
11. Recommended Tools List
12. Drawings and Diagrams
13. Certificates

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1. D801 MiniPurge

- General System Specification
Pressurized Motor Housing
Pressurized Motor Enclosure : A range of Electrical Motor housings
Classification : Zone 1 Group IIC
Volume (Litres) : Various, system settings determined by motor manufacturer.
Total Purge Flow Rate : To be supplied by customer and must include flow to compensate for leakage.
Estimated Purge Time : To be determined by 10 x volume.
Contents of Enclosure : Electrical motor.
Access covers : Special Tool required or Key Operated, door Interlock System not required.
Enclosure Pressure : Normal: 10 mbarg. (Alternative set-points are available) This is also the set
point of the Automatic Leakage Compensation Pressure Sensor (CLAPS
Sensor)
Enclosure Test Pressure : Motor Test Pressure = Relief Valve opening pressure x 1.5
MiniPurge

Control Unit Data
Model Number : 7XLC/ss/ET/OV/PA/PC Special Design Number: D801SYS
Option codes : ET = Electronic Purge Timer
: OV = Outlet Valve is pneumatically operated
: PA = Integral Ex e Power & Alarm terminal box
: PC = Pressurized Enclosure (Motor) Pressure Control Automatic
Leakage Compensation Valve (CLAPS system)
Action on Pressure Failure : Alarm and Trip (Isolate power / motor) User adjustable “Alarm Only”
System Type : ThinMani MiniPurgeSystem
Type of Operation : Automatic Leakage Compensation using the "Closed Loop Automatic
Pressurization System" (CLAPS)
Purge Flow Capacity : Up to 0.25m3/s (14,000 Nl/min) @ 420kPag (4.2 barg) inlet pressure. See
individual system specification sheet
Leakage Compensation
Capacity : Up to 0.085m3/s (5100 Nl/min) @ 420kPag (4.2 barg) inlet pressure
Enclosure Type : Stainless Steel 316
Mounting method : Wall mounting lugs & spacers. Fixing holes as per drawing D801-GA.
Temperature Limits : -20ºC to +55ºC ambient temperature.
Supply Pressure : Clean Dry Oil Free Air or Inert Gas. Pressure 420 – 800kPag (4.2 - 8 barg).
50 micron automatic drain supply Inlet filter & 1.6MPag (16 barg) regulator fitted.
Logic Regulator & Gauge : Fitted. Set to 230kPag (2.3 barg).
CLAPS Regulator & Gauge : Set to system requirements
Process Connections : Purge Supply: ANSI 150 B16.5 flange (size as per customer specification).
Outlet to Motor: ANSI 150 B16.5 flange (size as per customer specification).
Minimum Supply Line 50mm (2”) I.D Pipe
Reference points & signals: 1/8” NPT female
Visual Indicators : Alarm/Pressurized (Red / Green)
: Intermediate Low Pressure (Red / Green)
: System Purging (Black / 4 x Yellow LEDs to indicate elapsed time)
Motor Interlock Switch : DPNO electrical switch, contact ratings AC-15 250 Vac 4 Amps,
Ex d IIC T6
Low Pressure Switch : SPNO electrical switch, contact ratings AC-15 250Vac 4 Amps,
Ex d IIC T6
Intermediate Switch : SPNO electrical switch, contact ratings AC-15 250 Vac 4 Amps,
Ex d IIC T6
Signal Junction box : Stainless Steel, Ex e IIC T5 Gb (Tamb -20ºC to 55ºC) IP66 / Ex e IIC T4 Gb
(Tamb -20ºC to 60ºC) IP66. Mounted inside D801 system c/w terminals, front
access cover & access for glands on bottom of D801 system.

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Sensors (-0,+0.7 mbar) : Low Pressure calibration range: Minimum : 50Pag (0.5 mbarg)
Maximum : 500Pag (5.0 mbarg)
Default setting: 150Pag (1.5 mbarg)
Other Sensors (-0, +10%) : Intermediate Pressure calibration range. Minimum : 200Pag (2.0 mbarg)
Maximum : 600Pag (6.0 mbarg)
Default setting: 400Pag (4.0 mbarg)
Other Sensors (-10, +0%) : High Pressure calibration range. Minimum : 2 kPag (20 mbarg)
Maximum : 3.5 kPag (35 mbarg)
Default setting: 3 kPag (30 mbarg)
: Purging Flow OK set at Factory set to provide required
Purge flow rate
: CLAPS sensor calibration range Minimum : 1kPag (10.0mbarg)
Maximum : 1.5kPag (15.0mbarg)
Default setting : 1kPag(10.0mbarg)
Note:
There must be a 150Pa difference between the Minimum Pressure & Intermediate Sensor and a 500Pa difference between the
RLV lift-off point and the High Pressure. i.e. Minimum Pressure = 300Pa, Intermediate Pressure 500Pa, CLAPS Sensor 1kPa
RLV Lift off at 2kPa.
Purge Time : User selectable up to 99 (-0, +3 seconds) minutes in 1 minute increments.
Default set to 99minutes
Weight : 70 kg (154 lb)
Approvals ATEX Certificate: Sira 01ATEX1295X
0518 II 2 (2) G D
Ex [pxb] ia IIC T5 Gb
Ex [pxb] ia IIIC T100ºC Db
Tamb -20ºC +55ºC
IECEx Certificate: IECEx SIR07.0027X
Ex [pxb] ia IIC T5
Ex [pxb] ia IIIC T100ºC Db
Tamb -20ºC +55ºC
INMETRO – TUV TÜV 12.1462X
Ex [pxb] ia IIC T5 Gb
Ex [pxb] ia IIIC T100ºC Db
Tamb -20ºC +55ºC
For limitations and conditions of use refer to the applicable
certificate at the back of this manual.
Pressure Relief Valve (RLV) / Purge Outlet Valve with Integral Spark Arrestor
Type : RLV200/ss/FS
Bore : Purging Ø200mm, Relief Valve Ø200 mm
Relief Valve lift–off calibration : Minimum 2kPag (20 mbarg)
(+0,-20%) : Maximum 3.5kPag (35 mbarg)
: Default 3kPag (30 mbarg)
Flow rate : Factory set to 12000
Available flow rate: 7000, 8000, 10000, 12000 & 14000 Nl/min

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Material : Housing: Stainless Steel 316L
: Gasket : Neoprene
: Spark Arrestor Stainless Steel mesh
Mounting method : Rectangular cut-out & fixing holes as per drawing.
Weight : 23 kg (50.6 lb)

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2. Quick User Guide
Installation
•Mount the purge system as per the Hook-Up drawing.
•Always ensure the system has been installed as per the full instructions in section of the manual
titled ‘Installation of the System’.
•Always ensure all piping is clean and free of dirt & debris prior to connection to the purge system
or enclosure.
•Strongly recommend a local isolation valve on the air supply to the purge system is installed.
Note: Most faults are due to the air supply being restricted, the air supply pipe work installed being
too small or a drop in air supply pressure during purge.
Operation of System
•Once installed correctly turn on air supply.
Indicator Colour Status
Low Pressure Red Pressure Alarm, enclosure pressure too low
Intermediate Pressure Red Pressure Alarm, enclosure pressure too low
Purge Complete Black Purge flow too low, (or not in the purge mode)
•Purge system starts off in purge.
othe purge air will enter the enclosure
owithin the Relive Valve unit, Purge Outlet Valve will open
othe air will then exit the Relieve Valve housing, via the Spark Arrestor
Indicator Colour Status
Low Pressure Red Pressure Alarm, enclosure pressure too low
Intermediate Pressure Red Pressure Alarm, enclosure pressure too low
Purge Complete Black Purge flow too low, (or not in the purge mode)
•Once enough purge air flow is measured the system will start the timed purge cycle.
Start a stopwatch when the Purging Indicator flashes “Yellow”
Indicator Colour Status
Low Pressure Green Pressurized
Intermediate Pressure Green Pressurized
Purge Complete Yellow (Flashing) Purge Flow above the minimum
•After the purge has completed without interruption for the set purge time, the system will show
Purge Complete. Stop the stopwatch when the Purging Indicator turns "Black".
Indicator Colour Status
Low Pressure Green Pressurized and in Leakage Compensation mode.
Intermediate Pressure Green Pressurized
Purge Complete Black No longer in the purge mode
•Check that the purge time required has been met or exceed by the actual purge time recorded.
The actual purge time recorded must NEVER be less than the purge time required.
•System is now in Leakage Compensation mode and working correctly
If the system has not worked as expected check the installation thoroughly.
Read the section in this manual called “Commissioning”
If an obvious problem has not been highlighted and corrected then follow the checks in the section
“Fault Finding”.

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If the checks have been made and the system will still not work then please contact your local
distributor or EXPO.

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3. 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.
Depending on the model, the systems may be used in IECEx and ATEX Zone 1(21) and Zone 2(22) -
Categories 2 and 3 respectively.
MiniPurgesystems may be used for hazards of any gas group. However, apparatus associated with
the MiniPurgesystem, such as 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.
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
•ABS
•Polycarbonate
•Polyester (glass filled)

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4. Description and Principle of Operation
The MiniPurgesystem is pneumatic in operation, with electric interfaces.
“Pressurization” is a method of protection used in Zone 1 and Zone 2 Hazardous Locations to ensure
that the interior of an electrical enclosure, for example the motor housing, is free of flammable gas.
With the utilisation of the Expo MiniPurgesystem, the motor may be used safely in a hazardous
environment.
Pressurization is simple. Clean uncontaminated compressed air, or an inert gas, from a non-
hazardous area is admitted to the motor enclosure to keep the internal pressure at least 0.5 mbar
above the pressure outside. External flammable gas cannot enter the enclosure while it is
pressurized.
Before power can be switched on, the enclosure must be “purged” to remove any flammable gas that
might have entered the enclosure before it was pressurized. “Purging” is the action of replacing the
air inside an enclosure with air known to be free of flammable gas. The duration of the “purging” time
is normally ascertained on an electrical motor by performing a “Purge Test”.
At the end of the “Purging” cycle the system automatically switches to Leakage Compensation mode.
The Purge Outlet Valve is closed and the flow of purging air is reduced to a level where there is
enough flow of air to compensate merely for the leakage of air from the enclosure whilst maintaining
the minimum over-pressure state. Interface contacts are provided within the system to provide an
interlock to the motor control gear.
In the event of pressure failure within the motor housing the system will raise an alarm in the form of
visual indicators and a volt free contact depending on the specification of the system. The default
action on loss of pressurization by the MiniPurgeis “Alarm and Automatic Disconnect of Power”
(A&T – Alarm and Trip). This can be changed by the customer to “Alarm Only” (AO), please refer to
Section titled ‘Main Components’ - “Alarm Only” circuit.
The Motor MiniPurgesystem incorporates a "Closed Loop Automatic Pressurization System"
(CLAPS) whereby the system will detect a fall or rise in the motor internal pressure & automatically
compensate by increasing or decreasing the leakage compensation flow rate into the motor. This
system has been specifically designed to maintain a stable internal motor pressure during motor
start-up when pressure peaks or drops are particularly prevalent or when changes in pressure are
caused by running temperature variations.

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5. Main Components
Air Supply Filter:
The unit is provided with a 50-micron liquid / dust filter element as a precaution. The user of the
MiniPurgesystem must ensure that air supply is to the quality stated in ‘Air Supply Quality'
paragraph found in the Installation section.
Logic Air Supply Regulator:
This device provides the system with a stable logic pressure supply for consistent operation. The
pressure level is factory set to 230 kPag (2.3 barg) and can be verified by means of the integral
pressure gauge. It should only be adjusted if the gauge indicates that the regulated pressure is
incorrect.
Logic Manifold:
This black block contains most of the logic components in the system and can be thought of as a
pneumatic printed circuit board. It has internal passageways that interconnect the components with
facilities for connections to the off-manifold items. It incorporates the following major items:
Low Pressure Sensors:
The pressure inside the Pressurized Enclosure is monitored continuously by these devices.
When the pressure is correct i.e. above the minimum pressure specified for safe operation, it
provides a “Pressurized” output signal that can be seen by the operator e.g. displayed on a
local Red/"Green" visual indicator. The sensor is factory calibrated to operate on a falling
pressure at or above the minimum specified pressure.
Purge Flow Sensor:
The purge flow through the Relief Valve (RLV) / Purge Outlet Valve is monitored by this
device. When the purge flow is correct i.e. above the minimum purge flow specified for correct
purging, the sensor provides a “Purging” output signal that activates the timer switch. The
sensor is factory calibrated to operate on a falling flow rate at or above the minimum specified
flow rate.
Purge Timer:
When the PE pressure is correct and the correct Purge Flow is taking place, the Purge Flow
Sensor activates the Timer Switch allowing the Electronic Timer to initiate. The time delay is
determined by the pre-settable switches mounted on the Timer module. Whilst timing, a visual
indication of elapsed time is provided using 4 LEDs. The LEDs of the timing indicator will flash
in turn whilst the timer is running. LED1 will flash from 0 - 25% of elapsed time. LED2 from 25
- 50% of elapsed time. LED3 will flash from 50 - 75% of elapsed time. LED4 will flash from 75 -
100% of elapsed time.
When the Timer completes it energises the Intrinsically Safe solenoid “Timer Valve” for
approximately 1 second which allows a latch signal to the “Purge Complete” Valve.
“Purge Complete” Valve:
This valve receives the signal from the purge timer when the purge time has been completed
and checks that “Pressurized” signal is also still present. If both conditions are satisfied, a
“Purge Complete” output signal is produced which is sent to perform the following functions:
turn on the electrical supply to the PE, turn off the high purge flow and start the “Leakage
Compensation” mode. It will also provide a hold-on signal to maintain the system in “Leakage
Compensation” mode with the power switch on even when the Purge Timer has reset ready
for the next purge cycle whenever it is required.

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“Or” Gate:
This device provides the Purge Complete Valve with its hold-on function referred to above.
When either the “Timed Out” signal or the “Purge Complete” signal is present it allows the pilot
signal to be applied to the “Purge Complete” Valve.
“Alarm Only” circuit. The system normally will cut off the electrical power to the PE if the
enclosure pressure is too low. In certain circumstances, where local codes of practice allow,
the system can be altered to provide a hold-on circuit that will maintain the electrical power
supply to the PE while also providing a “Pressure Failure Alarm”. The user must respond to
the Alarm and either restores the pressure to the PE or otherwise make the installation safe
e.g. shut off the electrical supply. The decision to use the “Alarm Only” facility, and the length
of time during which the enclosure is allowed to operate un-pressurized, is the responsibility of
the user.
Warning:
It is potentially dangerous to energise the Pressurized Motor Enclosure in an un-pressurized
condition, when it is known there are potentially explosive hazardous gases in the area.
Motor Interlock (Purge Complete) Switch:
A Flameproof “Ex d II” Power Switch is located on the logic manifold which also contains the
pneumatic actuating piston. The cable from the switch is terminated in an “Ex e II T100ºC (Tamb -20ºC
to +55ºC) IP66” junction box.
Alarm/Pressurized Low Pressure Switch:
Like the Motor Interlock Switch this “Ex II” device is operated by the “Pressurized” signal and
provides the facility for a remote electrical system status indicator to show “Pressurized” or “Pressure
Failure Alarm”. The cable from the switch is terminated in an “Ex e II T100ºC (Tamb -20ºC to +55ºC)
IP66” junction box.
Intermediate Pressure Switch:
A Flameproof “Ex d IIC” Power Switch is located off the logic manifold. The cable from the switch is
terminated in an “Ex e II T100ºC (Tamb -20ºC to +55ºC) IP66” junction box.
CLAPS Sensor:
This sensor monitors the pressure within the motor and then sends a proportional control signal to
the "CLAPS Leakage Compensation Valve" to either increase or decrease the flow of air into the
motor enclosure to maintain a stable running pressure. The normal motor running pressure must be
determined prior to system start-up so that the CLAPS Sensor may be set to the desired level to
control the CLAPS Valve.
Visual Indicators:
Visual indicators are fitted to the MiniPurgeControl Unit to provide local status information to the
operator:
•The “Low Pressure” indicator has two states:
Red = “Pressure Alarm” i.e. “Enclosure Pressure too low”
Green* = “Pressurized”
•The “Intermediate Pressure” indicator has two states:
Red = “Pressure Alarm” i.e. “Enclosure Pressure too low”
Green* = “Pressurized”
•The “Purge Complete” indicator has two states:
Black* = “Purge flow too low” (or not in the purge mode)
Yellow (Flashing)= “Purge Flow above the minimum”

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* This combination is the indication during normal operation of the Pressurized Enclosure after the initial purging process
has been completed.
Relief Valve (RLV) / Purge Outlet Valve:
•The RLV unit allows the purge air to exhaust safely from the enclosure via an in-built Spark
Arrestor. The Spark Arrestor is designed to prevent the emission of arcs, sparks and
incandescent particles produced by normal operation or an electrical fault within the PE.
•During purge cycle, a pneumatic cylinder operates a Purge Outlet Valve that lets the air in the
enclosure vent out through the RLV. When the system changes to leakage compensation mode,
the Purge Outlet Valve is closed and the enclosure sealed.
•Purge air passes through the RLV and a correctly selected orifice plate will ensure that the Purge
Flow Sensor is activated once the selected purge flow has been attained. This is via a preset
pressure differential across an orifice.
•The RLV unit has an in-built Relief Valve sized to ensure that, if the air supply pressure rises up
from the specified maximum Normal Working Pressure, the internal enclosure pressure will not
exceed the PE specified maximum working pressure.
/PA Terminal Box
Increased Safety
Ex e IIC T5 Gb
Ex tb IIIC T1000C Db IP66
Tamb -20ºC to +55ºC
Ex e IIC T4 Gb
Tamb -20ºC to +60ºC
The Terminal Box is “Increased Safety “ (Ex e) certified and incorporates the terminal connection
points for the alarm & interlock circuits. All contacts provided are Volt free (dry).
Cable entry methods (e.g. conduit or glands) shall conform to IEC / European or other relevant local
codes. The main requirement is that IP54 or IP66 (for dust applications), or better ingress protection
must be provided by the use of seals or washers. Cable glands must be “Ex” certified if they are non-
metallic.

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6. Installation of the System
This equipment 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 in accordance with relevant standards, such as IEC / EN
60079-14, and any local codes of practice that are in force.
Air Supply Quality
The MiniPurge®system should be connected to a protective gas supply, which is suitable for purging
and pressurization.
The supply pipe connection to the MiniPurge®must be appropriate for the maximum input flow rate
for the application.
The air supply must be regulated at a pressure less than the maximum stated inlet pressure.
The air supply must be: clean, non-flammable and from a non-hazardous location. The air should be
of Instrument Air Quality. Although the purge control system will operate with lower air quality, its
operational life will be adversely affected. The equipment that is being protected by the MiniPurge®
may also suffer because of poor air quality.
With reference to BS ISO 8573-1: 2010, Instrument Air is typically specified as:
Particle Class 1
In each cubic metre of compressed air, the particulate count should not exceed 20,000 particles in
the 0.1 to 0.5 micron size range, 400 particles in the 0.5 to 1 micron size range and 10 particles in the
1 to 5 micron size range.
Humidity or pressure dew point
The dew point, at line pressure, shall be at least 10 °C below the minimum local recorded ambient
temperature at the plant site. In no case, should the dew point at line pressure exceed +3 °C.
Oil Class 2
In each cubic metre of compressed air, not more than 0.1mg of oil is allowed. This is a total level for
liquid oil, oil aerosol and oil vapour.
When an inert gas is being used to supply the purge system, risk of asphyxiation exists. Refer to
Application Suitability section.
Before connection of the air supply to the purge system, the supply pipe work should be flushed
through with instrument quality air to remove any debris that may remain in the pipes. This must be
carried out for at least 10 seconds for every meter of supply pipe.
Unless a supply shut-off valve has been fitted to the MiniPurge®system, an external shut-off valve
with the same, or larger, thread size as the Control Unit inlet fitting should be fitted by the installer to
prevent any restriction of purge flow.
The purge air from the MiniPurge® Control Unit should be piped within the pressurized enclosure to
ensure purging of potential dead air spots.
The purge system is fitted with an internal regulator factory set to 3 bar feeding the logic..

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Warning: The correct logic supply pressure is vital to the reliability and calibration of the
system therefore should not be adjusted.
Location
The MiniPurgeControl Unit (CU) should be installed either directly on or close to the Motor PE. If
not installed on the PE it should be as close as possible. It should be installed so that the system
indicators and certification labels may be readily observed.
Relief Valve: To achieve efficient purging, the points where air enters and exits the PE should
normally be at opposite ends of the enclosure. The RLV must be mounted vertically and there should
be a minimum clearance of 600mm (24”) around the Spark Arrestor (purge outlet).
It is important that the interior and exterior of the Spark Arrestor is kept clean and debris is not
allowed to accumulate which might affect the calibration of the device. In particular the exterior of the
Spark Arrestor should not be painted or blocked off in any way.
Serial numbers 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.
Piping Unless the MiniPurgeis directly connected to the PE, any piping, conduit and fittings used to
connect to the CU to the PE should be metallic or appropriate to the environment into which the
system is installed. No valve may be fitted in any tube connecting the CU to the PE. Additional
consideration should always be given to local codes of practice.
Multiple Enclosures This purge system is not suitable for multiple enclosures.
Provision and Installation of Alarm Devices The system has a Minimum Pressure Sensor set to a
pressure of least 0.5 mbar. When the PE pressure is above this set point the sensor produces a
positive “Pressurized” signal. The relevant indicator on the CU will change from Red to “Green”.
When the enclosure pressure falls below the set point of the sensor the “Pressurized” signal is
removed, i.e. absence of the signal indicates a “Low Pressure Alarm" condition. The indicator on the
CU will change from Green to “Red”. There are volt free (dry) contacts available within the Terminal
Box for remote usage. The user must make use of this alarm facility in accordance with the local
Code of Practice for “Action on Pressure or Flow Failure”. Most Codes include the following
recommendations:
•ATEX Category 2 (Zone 1) Installations: Alarm and Automatic Trip off Power.
•ATEX Category 3 (Zone 2) Installations Alarm Only on pressure or flow failure with power being
removed manually.
Power Supplies and their Isolation 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
equipment such as “volt-free” (dry) contacts within the PE. For motor applications it is normally via
the “Motor Interlock Switch.”
The Motor Interlock Switch is a BARTEC 07-2511-1322 Limit Switch, “Ex d IIC Tamb -20ºC +60ºC”
IECEx & ATEX certifications IECEx PTB 07.0045X & PTB 00ATEX1093X.
Rated voltage/current: 250Vac, 4A (AC-15)

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This switch is double-break switch, that provides two independant contacts. These two contacts shall
be connected in series and shall be used to isolate the power into the motor. This may be achieved
by means of a contactor or other switching device suitable for the application.
It is the responsibility of the user to ensure that switch is operated only within the technical limits that
apply to it, i.e. rated current & voltage shall not be exceeded.
The two contacts of the switch are terminated, and accessible by the user, in an Ex e Terminal box.
The switch must be replaced after any short circuit that occurs in the main circuit. The switch is a
piece of encapsulated equipment and it is therefore not posible to check the state of the switch
contacts. It is not permisible to technically modify the switch.
Before commissioning check that the Ex e terminal box is clean, the connections have been made
properly, the cables have been laid correctly and all screws in the terminals are tightened securely.
The safety related with the use of this switch is responsibility of the user. All electrical installations
must conform to the local codes of practice.
Exception: Power to other apparatus that is already suitable for the hazardous area need not be
isolated by the MiniPurgesystem.
In all cases the application and the isolation of the power must be controlled by the MiniPurge
system using the “Motor Interlock” signal.
The electrical installation must conform to the local codes of practice.
No switches are permitted between the Power Switch and the MiniPurgesystem other than an
authorised “Manual Override” circuit.

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7. Commissioning
Initial Commissioning
•The "CLAPS Leakage Compensation Valve" can be set finally only when the enclosure has been
installed in its permanent operating location.
•Check that the system has been installed in accordance with Expo Instructions.
•Disconnect the supply pipe from the inlet to the MiniPurgesystem and blow clean air through it
for at least 10 seconds per meter of length to remove any debris, oil and condensation.
Commissioning
Proceed as follows:
•Check all connections and RLV is fitted correctly with no obstructions to the purge exhaust.
•Open the external supply shutoff valve, where fitted.
•Check that the internal logic pressure gauge reads 230 KPag / 2.3 barg
•Increase the leakage compensation pilot supply until the enclosure pressure rises above the low
pressure setting. At this point the system will switch to purge. Note the leakage compensation
pilot pressure.
•Check that the pressure gauge on main air supply reads at least 420 Kpa / 4.2 barg. Purging flow
will start.
•Check the Pressure Relief Valve is correctly set by disconnection the Minimum Pressure sensing
“Green” pipe at the bulkhead fitting on the input to the MiniPurge, this will disable all of the
pressure sensors.
•Connect a manometer to the bulkhead fitting, with a 4mm nylon tube, from where the Minimum
Pressure sensing “Green” pipe was removed.
•Close the Purge Flow Restrictor valve and turn on the compressed air to the MiniPurge. Increase
the leakage compensation pilot pressure to 3.5 barg Then, very slowly, open the Purge Flow
restrictor until the pressure Relief Valve opens and check the opening pressure is within
calibration. This test can be completed several times to ensure compliance and repeatability. Go
to Maintenance of the System if the Relief Valve needs to be recalibrated.
•Close the Purge Flow Restrictor and shut-off the external compressed air supply. Remove the
manometer and replace the Minimum Pressure sensing pipe in the bulkhead fitting. Return the
leakage compensation pilot pressure to the value noted above.
•The setting of the Purge Flow Rate. Turning on the compressed air to the MiniPurgeand
gradually open the Purge Flow Restrictor valve until the “Black” / Yellow indicator changes to
Black / “Yellow (flashing)”, typically motor internal pressure should be approximately 13 – 16
mbarg.The flashing Yellow indication confirms correct Purge Flow Rate.
•At this time the "Pressurized" indicator should be “Green” and the "Purging" indicator should be
flashing “Yellow”.
WARNING: When opening the Purge Flow Restrictor valve ensure the overpressure within the
motor does not exceed the pressure Relief Valve setting.
•The purge timer will start as soon as the "Purging" indicator flashes “Yellow”. Check that the time
delay between the indicator flashing “Yellow” (Purging) and returning to ‘Black’ is not less than the
minimum time required to purge the PE. Times in excess of the minimum are permitted.
•After the purge time has been completed, the Purging Valve will switch to leakage compensation
and the air flow into the enclosure will be controlled by the CLAPS sensor and the CLAPS pilot
pressure. The CLAPS pilot pressure should be adjusted to achieve the enclosure pressure
required which is marked on the CLAPS sensor, this being the 30% point of the dynamic range of
the sensor.
•The motor enclosure pressure should be stable at the set value with no perceptible “hunting”.

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•The setting of the CLAPS Sensor is factory calibrated to the normal working pressure expected in
the motor, typically 10 mbarg. The pressure in the Motor should be stabilized as close as
possible to this figure.
Additional Checks
•After proving the system is working correctly it may be a requirement to check the calibration of
the Pressure Sensors within the MiniPurgeControl Unit. To complete these tests use a
manometer and connect to the MiniPurgeControl Unit Test Point (on the top of minimum
pressure sensor - remove the red plug and use 4mm OD nylon tube) during commissioning.
•The calibration of the Pressure Sensors is set on a falling pressure.
•Close the Purge Flow Restrictor valve and then gradually slowly open until above the minimum
Pressure Sensor setting, Alarm indicator turns from Red to “Green”. Gradually close the Purge
Flow Restrictor valve until the indicator turns back to Red and take a note of the reading. Check
this reading against the “Test, Inspection and Setting Sheet”. It should always be at or above this
setting.
•The same tests can be performed for the all the other Pressure Sensors incorporated within the
MiniPurge Control Unit.
•Once all tests are completed reset the Purge Flow Restrictor valve and retest the MiniPurge
System.
•Go to Maintenance of the System if the Pressure Sensor needs to be recalibrated.
Normal operation
Turn the air supply valve On or Off to start or stop the system. After this, the Pressurizing and
Purging sequence is entirely automatic.

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Brass Nozzle
Remove Sensor by
unscrewing anti-clockwise.
8. Maintenance of the System
The maintenance recommended for the system consists of the following, supplemented by any
additional local requirements imposed by the local Code of Practice.
Expo recommends that the commissioning tests be repeated at every six to 24 months, dependent
on the environment. 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 with a
spare.
•Check the condition of the air supply filter element. Clean or replace it as necessary.
At least every two years, the following additional checks are recommended:
•Apparatus is suitable for the Hazardous Location
•There are no unauthorised 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
The Intrinsically Safe Battery Pack should be changed at least every three years, and the
commissioning tests repeated. After the timing phase has elapsed, the battery may be ‘hot-swapped’
in a hazardous environment without effecting the operation of the MiniPurge Ex px system
Recalibration of the Pressure Relief Valve (when necessary)
•Before making any adjustment, make sure the pressure Relief
Valve seat is free of contamination particles.
•To adjust the lift off pressure of the overpressure Relief Valve
you will require an 8mm spanner and a 2.5mm Allen Key.
•While holding the central Allen Screw in position loosens the
retaining nut.
•Adjust the Allen key clockwise to increase the lift off pressure,
adjust Anti-clockwise to reduce the lift off pressure. "The
adjustment is very sensitive and it is recommended that one
half turn between tests should be adequate until you are
familiar with the device".
•Retighten the locking nut while holding the adjustment screw in position before each test.
Recalibration of the Pressure Sensors (when necessary)
The brass nozzle is sealed into position using Loctite thread
sealant. This may require heating slightly to soften prior to
making any adjustment to avoid damaging the soft brass
nozzle.
•The adjustment is very sensitive so only turn the nozzle 1
or 2 mm until you have an idea of cause and affect when
calibrating. Clockwise reduces the pressure setting.
Allen Screw & Lock Nut

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9. Fault Finding
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 affected 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 the many of the components fitted are
plug-in or chassis 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 for investigation, with a full report of the fault and the system Serial Number.
As with any pneumatic system the greatest enemies are water, oil and dirt in the air supply. For this
reason the air system must always incorporate a dust and water filter to provide air to instrument
quality. This will protect not only the purge system but also the equipment being purged. The
filtration must be provided by others. However dirt can enter from other sources and it is vital
therefore that the procedures described in "Installation" section are carried out before using the
system for the first time, or following any disconnection of the pipe-work. Failure to perform this work
may cause damage that will not be covered under warranty.
Before making the following checks verify that both the main air supply pressure to the MiniPurge
system & the regulated pressure to the logic are as specified on the system specification sheet.
Also ensure that the air supply pressure does not drop during purge below the minimum supply
pressure. Most faults reported are due to insufficient air supply being maintained throughout the
duration of a purge cycle.
System Purges Correctly but the Alarm Comes ON at the End of Purge Time and the Purging
Cycle is Repeated.
Cause 1:
The CLAPS Leakage Compensation Valve setting is too low and the PE is tripping out after purging
due to low pressure.
Try increasing the setting of the CLAPS Leakage Compensation pilot pressure to raise the pressure
in the PE at the end of purging.
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 any debris stuck on the face of the RLV disk, perhaps held there because of the magnet?
•Has the PE door / covers been closed and all conduit / cable glands sealed?
•Is the PE leaking too much?
•Is the pressure sensing tube damaged and leaking?
Cause 3: System fault?
If checks above reveal that the PE is correct, the fault probably lies in the CU. The basic operation of
the Minimum Pressure Sensor can be checked by unscrewing the 60mm diameter diaphragm
housing and sealing the 12mm threaded hole in the top of the valve module. This can be
accomplished by using a rubber block. The valve should operate and the indicator turns "Green". If
indicator turns "Green" it is likely that the pressure sensor diaphragm needs re-calibrating or
replacing.
Relief Valve Opens (Continuously or Intermittently)
Cause 1: The PE pressure is too high.
The CLAPS Leakage Compensation Pilot Pressure is too high. Adjust the CLAPS LC Pilot pressure.

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Cause 2: Debris on the RLV disk allowing air to leak from the valve. Remove the RLV cover and
clean the valve disk.
"Purging" Indicator will not flash yellow during purging
Cause 1: Insufficient Purging Flow due to inadequate air supply pressure. Check the air supply
pressure at the inlet to the CU when purging is taking place. Excessive pressure drop in the supply
pipe is a very common cause of this problem. The pipe bore must be at least the same size of the
CU inlet fitting.
Cause 2: Excessive PE leakage. Check around the PE when purging is taking place. Any significant
leakage must be cured. Has a Leakage Test been done? The total leakage at the Purge Outlet Valve
should not exceed 10% of the Purge Flow Sensor setting. Check for leakage down the cables or
conduit.
Cause 3: 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.
Cause 4: The Intrinsically Safe Battery Pack may be discharged and require replacement.
Cause 5: Ensure the ‘System Purging’ pneumatic OR switch output signal is present. If this is not the
cause the Electronic Timer circuit may be faulty. Due to the critical nature of this product we
recommend a new timer is fitted. This should be completed by a trained Service Engineer
System fails to operate when the Motor Interlock Switch closes after the Purge Time has
elapsed?
Cause 1: Is power available? Is the power isolator closed? Are the fuses or circuit breaker OK?
Cause 2: System fault? Timer not timed out?
•Has the "Purging" indicator been flashing “Yellow” for the whole of the purge time?
•Is the logic pressure gauge setting correct?
•The Timer setting may be reduced for test purposes down to 01 minutes. Check the operation on
the new purge time. If it works OK reset the time to the original setting. Finally recheck the purge
timer at its full setting.