ML435 | v23
Page
16
Expo Technologies UK
T: +44 (0) 20 8398 8011
Expo Technologies US
T: +1 (440) 247 5314
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• 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 Restrictor Valve, ensure the over pressure within the pressur-
ized enclosure does not exceed the pressure relief valve setting.
13.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.
14.After the purge has been completed, the Purge 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.
15.Gradually turn the CLAPS Regulator anti-clockwise to reduce enclosure pressure.
16.Reduce regulator until intermediate sensor causes contacts to open.
17.Check the manometer on the minimum pressure sensor.
18.Continue to reduce the CLAPS Regulator to test the minimum pressure sensor.
19.To check operation of Minimum Pressure Sensor, check readings on manometer as system will
automatically re-purge when it reaches minimum pressure.
20.While the system re-purges, return the CLAPS Regulator to the initial setting.
21.If minimum pressure is below the set point, refer to the Recalibration section
22.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.
23.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 Relief Valve unit by turning the adjuster screw clockwise.
24.To test the CLAPS settings, create a leak in the system by removing a bolt or losening a gland plate in order
to create a 15mm hole. Remember to replace bolt or retighten gland plate after testing.
25.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.
26.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.
