ML435 | v23
Page
20
Expo Technologies UK
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Expo Technologies US
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Relief Valve opens (continuously or intermittently)
System enters purging but purge indication does not occur.
System begins purging but cycles fail to complete
Fault Location
Cause
Solution
Pressurised Enclosure
Enclosure pressure is too high
due to CLAPS Regulator being
open to far.
Adjust the CLAPS Regulator.
Relief Valve Unit
Debris on the Relief Valve disk
allowing air to leak from the valve.
Remove Relief Valve cover and clean
the valve disk.
Fault Location
Cause
Solution
Air Supply
Insufficient flow rate due to
inadequate air supply pressure.
Often due to pressure drop in the
supply pipe.
Static pressure of 5 barg must be
maintained during purge
• Check air supply pressure at the
inlet to the control unit.
• Ensure that the supply pipe bore is
suitable for the flow rate
Pressurized Enclosure
Excessive leakage from the
pressurized enclosure.
• Check around the enclosure while
purging is taking place.
• Total leakage at purge outlet valve
should not exceed 10% of purge
flow sensor setting.
• Check for leakage down cables
and conduit.
Pipe Work
Tubing from Relief Valve flow
sensing point not air tight.
• Ensure fitting nuts are tightened.
• Check for tube damage.
• Repair as necessary.
Relief Valve Unit
Relief Valve opening during purge • Check enclosure pressure on start
up is less than Relief Valve lift off
pressure.
MiniPurge Control Unit
Flow sensor setting incorrect
• Check the pressure is correct on
the flow sensor.
Fault Location
Cause
Solution
Electronic Timer
Time set to 00
• Reset timer to correct purge
time.
The intrinsically safe battery pack
is discharged
• Replace as necessary .
