Vmac RAPTAIR-G30, Service Manual

Page: 65 / 96

VMAC
– Vehicle Mounted Air Compressors
Toll Free: 1-888-241-2289
Fax: 1-250-740-3201
63
Compressor Regulation and Throttle
Actuator Testing
The air pressure (inlet valve control) and engine rpm (throttle actuator) are
controlled by the unloader valve. As air pressure from the unloader valve
increases, it forces the throttle actuator to reduce engine rpm. Once the
system has built to full system pressure (150 psi) the force from the
unloader valve will set the throttle to base idle.
The following testing is for systems set at factory pressure
(150 psi).
With the system off and depressurized:
1) Remove the WHASP shroud.
2) Remove the ball valve fitting to accommodate the test tool.
3) Install a test tool on the system outlet (Figure 46).
4) Use a
“T” fitting to install a 200 psi gauge on the 1/4 in throttle tube.
(Figure 46).
Start the gas drive, and monitor both pressure gauges:
5) As the pressure indicated on the VMAC test tool gauge reaches 150
psi, the gauge connected to the1/4 in PTFE tube should read 150 psi.
If the pressure on the gauge connected to the1/4 in PTFE tube does
not rise, confirm the manual unloader valve has not been adjusted. If
the unloader valve has not been adjusted the discharge valve needs
to be replaced.
6) As the pressure indicated on the gauge connected to the1/4 in PTFE
tube reaches 150 psi, the throttle actuator rod should move outwards
and the engine rpm should decrease.
If the throttle actuator rod does
not move, diagnose or replace the throttle actuator.
7) When the system pressure (indicated on the VMAC test tool) reaches
150 psi, the pressure indicated on the gauge connected to the 1/4 in
PTFE should hold steady at 150 psi.
If the pressure does not hold,
check for air leaks, or a defective throttle actuator.
8) Slowly open the test tool ball valve, the pressure on both gauges
should drop at approximately the same rate. If the pressures do not
drop at the same rate, the air bleed muffler (the muffler connected to
the compressor inlet) may be plugged.