Vmac VR70 - Page 38

VMAC – Vehicle Mounted Air Compressors
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36
SYMPTOM
POSSIBLE CAUSE
CORRECTIVE ACTION
Excessive air
pressure
Pressure regulator
valve too high.
Reduce system pressure by
adjusting pressure regulator
valve.
System return line
blocked or frozen
Clear or replace the line.
Engine stalls when
compressor is
activated.
System is under
pressure.
Allow sufficient time for blow-
down.
Blow-down valve not
working.
Replace blow-down valve.
RPM setting too low or
throttle not set
correctly.
Readjust RPM and throttle
settings for optimum operation.
Throttle control not
connected properly at
foot pedal
Check for proper connections.
Belt squeals when
compressor switch is
activated.
System is under
pressure.
Allow 10 seconds for blow-down.
Blow-down valve not
working or muffler is
plugged.
Replace blow-down valve or
clean muffler.
Improper belt tension.
Check belt tensioner.
Belt is glazed.
Replace belt.
Frequent relief valve
operation.
Pressure regulator
setting too high.
Adjust pressure regulator setting
below 160 PSI / 1103 KPA.
Pressure control line
plugged or frozen.
Remove the pressure control line
and clear any obstructions. (Blow
out.)
Relief valve defective.
Replace relief valve.
Power fuse blows.
Short to ground in the
control circuit.
Locate and correct short or
replace control panel.
Incorrect fuse.
Install correct OEM fuse.
Incorrect wiring.
Repair wiring according to wiring
diagram.
Low air pressure.
Air flow is too high.
Reduce consumption.
Throttle control set too
low.
Increase maximum RPM
settings.
Pressure regulator
valve set too low.
Increase pressure by adjusting
pressure regulator valve.
Engine RPM
excessive on initial
startup and during
operation.
Maximum RPM setting
is too high.
Reduce maximum RPM setting
throttle control or reset cable
nipple.
Idle-down pressure is
too high.
Reduce idle-down setting of the
throttle control.