7. Troubleshooting Guide
7.1 Symptom
Drive will not start nor
cycle with at least 25
psi drive pressure.
Drive will not cycle
under load and pilot
vent leaks air
continuously.
Drive will not cycle.
Mufflers leak drive air
with very audible
"hiss".
Drive cycles but gas
section(s) does not
pump. (End cap does
not heat up)
Air Driven Gas Booster Compressor, 8" Drive AG Series • OM-12S
7.2 Possible Cause
Air supply blocked or inadequate.
Cycling valve spool binding.
Either pilot valve stem too short.
Exhaust or vent "iced up".
Mufflers plugged.
Broken pilot charge valve spring (cycling
valve end) causing it to stick open. Then
the pilot vent valve cannot "dump" enough
pilot pressure so it remains held open by
the drive piston.
Defective o-ring on pilot charge valve
(cycling valve end) causing high leakage
into the pilot system.
Insufficient drive air volume causing
cycling spool to hang up in midstroke or
drive-piston o-ring to bypass air.
Shrinkage or damage to spool seals
and/or large drive piston seal.
Check valve(s) not seating, and/or
leakage of plunger or piston seal
(paragraphs 5.6, 5.7).
Check air supply and regulator.
Clean spool by following cycling
valve disassembly instructions.
(Ref. paragraph 5.2)
Replace defective pilot valve.
Too much moisture in drive air.
Install better moisture reduction
system.
Remove, disassemble and clean
mufflers.
Replace spring.
Replace o-ring.
Increase drive air line size.
Inspect spool seals first.
(paragraph 5.2 ) If damaged,
replace and retest. If not
damaged, disassemble drive
and check large o-ring size per
Figure 9 and paragraph 5.5.5.
See compression check
procedure and analysis
(paragraph 6).
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7.3 Remedy