VMAC - Vehicle Mounted Air Compressors
VMAC Technical Support: 888-241-2289
VMAC Knowledge Base: kb.vmacair.com
65
Symptom
Possible Cause
Corrective Action
Compressor building above
set pressure (Verified by
pressure gauge) or pressure
relief valve venting at 200 psi.
Pressure control tube plugged
or frozen.
Remove and clear the tube.
Defective inlet or poppet
O-ring.
Replace O-ring.
Defective inlet valve.
Replace inlet assembly.
Plugged or restricted pressure
control tube
Replace components as
needed.
Unloader valve out of
adjustment or failed.
Replace unloader valve.
Symptom
Possible Cause
Corrective Action
Compressor will not build to
set pressure
(Verified by pressure gauge).
Defective downstream
equipment (Filter Regulator
Lubricator, fittings, hose reel.
Replace as required with
suitable components.
Unloader valve manually
activated.
Manually disengage unloader
valve.
Excessive leakage through
blowdown muffler.
Replace blowdown shuttle
valve.
Plugged or dirty compressor
air filter.
Replace air filter.
Drive belt slipping.
Check belt.
Leaks in air lines.
Replace components as
needed.
Pressure relief valve leaking.
Replace pressure relief valve.
Inlet valve regulator set too
low.
Adjust inlet valve regulator.
See page 70.
Symptom
Possible Cause
Corrective Action
Engine Stalls.
Low fuel in engine.
Add fuel to engine.
Contaminated fuel.
Clean fuel tank and
carburetor and fill with clean
fuel.
Compressor pressure set too
high.
Lower compressor air
pressure to approx. 140 psi.
Ensure unloader activates
(rpm decreases).
Starting compressor under
pressure.
Ensure system is
depressurizing on shut down.
Operating at too high of an
elevation.
See section on elevation on
Low engine oil.
Add oil to engine.
Spark plug gap.
Replace spark plug.
Spark arrester clogged.
Clean or replace the spark
arrester.
Mounted in enclosure.
See enclosure mounting
parameters on page 16.
