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ML548_ES | v3
Expo Technologies UK
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• Raise the internal pressure by turning the CLAPS regulator clockwise until the
Low-Pressure Alarm Indicator turns green. This will activate the Purge Flow regulator & Purge Outlet
Valve. The pressure will fluctuate as the Purge Outlet Valve opens/closes. This is normal.
• Gradually open the Purge Flow Regulator until System Purging Indicator flashes yellow.
• The flashing yellow indicator confirms the timer has started.
• The differential pressure should be greater than 6.4 mbarg.
• The relief valve is supplied with different orifice plates for the specified flow rate. This orifice plate is
held in position by two M3 screws and can easily be changed by removing the large cover plate from over
the outlet valve assembly and screws.
Warning: When opening the Purge Flow Regulator Valve, ensure the over pressure within the enclo-
sure does not exceed the pressure relief valve setting.
14.The purge timer will start as soon as the Purging Indicator
flashes yellow
. Check that the time delay
between the indicator turning to
yellow (flashing)
and returning to
black
is not less than the minimum
time required for complete purging of the pressurized enclosure. Times in excess of minimum are
permitted.
15.After the purge has been completed, the Purge Outlet Valve will close and the air flow into the pressurized
enclosure will be controlled by the CLAPS Regulator. The initial setting may be too high or too low.
16.Gradually turn the CLAPS Regulator anti-clockwise to reduce enclosure pressure.
17.Reduce regulator until intermediate sensor causes contacts to open.
18.Check reading on manometer matches calibration label on pressure sensor.
19.Continue to reduce the CLAPS Regulator to test the minimum pressure sensor.
20.To check operation of Minimum Pressure Sensor, check readings on manometer as system will
automatically re-purge when it reaches minimum pressure.
21.While the system re-purges, return the CLAPS Regulator to the initial setting.
22.If minimum pressure is below the set point, refer to the Recalibration section
23.If the setting is too high, continual rising and falling of the enclosure pressure will be seen as the CLAPS
Regulator automatically shuts off and reinstates the flow. The CLAPS Regulator should be adjusted to
reduce the flow into the pressurized enclosure by turning the adjuster screw anti-clockwise.
24.If the initial setting is too low the CLAPS Regulator may not provide enough air flow causing a gradual
decline in enclosure pressure. To increase the flow into the pressurized enclosure, adjust the CLAPS
Regulator by turning the adjuster screw clockwise.
25.To test the CLAPS settings, create a leak in the system by removing a bolt or loosening a gland plate in
order to create a 15mm hole. Remember to replace bolt or retighten gland plate after testing.
26.The setting of the CLAPS Sensor is factory calibrated to the normal working pressure expected in the
pressurized enclosure, typically 10 mbarg. The pressure in the pressurized enclosure should be stabilized
as close as possible to this figure. This can be checked by a manometer attached to the minimum pressure
sensor.
27.Remove the air supply to the system, remove all test equipment and replace all plugs.
Normal Operation
For normal operation of the system, after commissioning has been carried out it is possible to turn the air
supply valve on or off to start or stop the system. After this, the purge and pressurization sequence is
automatic.
