Atlas Copco PNS 1250 Cud S3A/T3 APP, Instruction Manual

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7.3 Trouble shooting
Symptom Possible cause Corrective action
Compressor loaded automatically
to full capacity after starting Loading solenoid valve stuck in loaded position. Remove and check loading solenoid valve.
Replace valve if necessary.
Air intake throttle valve in open position. Check position throttle valve.
Disconnect loading solenoid valve from throttle valve housing
and connect independent compressed-air line to throttle valve
housing. Repeatedly admit air and listen for opening and
closing sound of throttle valve. If sound is not evident, remove
unloader valve assembly, dismantle and inspect.
Replace parts where necessary.
Compressor does not deliver air or
not immediately after loading
solenoid valve has been energized. Diaphragm of unloader piston cracked. If air blows from venting device, open unloader piston cover
and replace diaphragm.
Air intake throttle valve stuck in closed position. Disconnect loading solenoid valve from throttle valve housing
and connect independent compressed-air line to throttle valve
housing. Repeatedly admit air and listen for opening and
closing sound of throttle valve. If sound is not evident, remove
unloader valve assembly, dismantle and inspect. Replace parts
where necessary.
Air leaks in regulating system. Same action as above.
Loading solenoid valve out of order. Check loading solenoid valve and electric wiring. Replace
valve, if necessary.