Bendix Commercial Vehicle Systems AD-RP PuraGuard Oil Coalescing Remote Purge Air Dryers - Manual (Page 23)

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Bendix ® AD-RP ™ AIR DRYER TROUBLESHOOTING CHART
SYMPTOMS CAUSE REMEDY
7. Unable to build air
system pressure.
A. Bendix ® AD-RP ™ air dryer
purge control line incorrectly
connected to governor.
A. Check that the purge control of the AD-RP air
dryer is connected to the UNL (unloader) port on
governor.
B. Air trapped in the purge
control line (between the
governor and the AD-RP air
dryer.)
B. Inspect for kinked, plugged, damaged hose tubing
or fi ttings. Check for undrilled fi ttings or restricted
hose or tubing fittings. Repair or replace as
necessary.
C. Governor malfunction. C. Test the governor operation. Repair or replace as
necessary.
D. Compressor unloader
mechanism malfunction.
D. Test the compressor unloader mechanism for
proper operation. Repair or replace as necessary.
E. The AD-RP air dryer purge
valve piston is frozen open.
E. Check the operation of the AD-RP air dryer heater
and thermostat. Repair or replace as necessary.
F. The AD-RP air dryer purge
valve piston is stuck.
F. Check the operation and repair or replace as
necessary.
8. Air dryer does not
purge or exhaust air.
Note: this symptom
often precedes
Symptom #9 if
desiccant cartridge is
not replaced.
A. Air is not reaching the
AD-RP air dryer purge
control port.
A. Test to determine that air fl ows through the purge
control line to the purge control port on the AD-RP
air dryer when the compressor is unloaded. Check
for undrilled fi ttings. Check if the purge control line
is broken, not connected, mis-connected, frozen or
damaged. Inspect, repair or replace as necessary.
Replace desiccant cartridge.
B. The AD-RP air dryer purge
valve or piston is frozen
closed.
B. Check the operation of the AD-RP air dryer heater
and thermostat. Repair or replace as necessary.
Replace desiccant cartridge.
C. Extremely high air usage
requirements on the
vehicle.
C. Refer to the Vehicle Application Requirements
section of this manual and verify application.
(continued)