ML511 | v13
Page
18
Expo Technologies UK
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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
Recommended Spares List
Fault Location
Cause
Solution
Pressurized 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 airtight.
• 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.
Part Number
Description
S0015/250
Filter kit for main air supply filter/regulator
S0030/606
Purge flow sensor factory set to 6.4 mbarg
S0030/016
Minimum Pressure sensor, must be factory set to the value as stated on the
Customer Test and Inspection Sheet
S0030/588
CLAPS Sensor must be factory set to the value as stated on the Customer Test and
Inspection Sheet
