13
BENDIX
®
AD-IS
®
AIR DRYER AND RESERVOIR SYSTEM
TROUBLESHOOTING CHART
SYMPTOM
CAUSE
REMEDY
5. Cannot build system air
pressure.
A. Supply pressure to the air dryer is not
suffi cient.
A. Ensure the supply pressure to the air dryer is greater than
110 psi after the system charges.
B. Kinked or blocked (plugged) discharge
line.
B. Check to determine if air passes through discharge line.
Check for kinks, bends, excessive carbon deposits, or ice
blockage.
C. Excessive bends in discharge line
(water collects and freezes).
C. Discharge line should be constantly sloping from compressor
to air dryer with as few bends as possible.
D. Pressure protection valve(s) in air
dryer will not open.
D. Replace air dryer (pressure protection valves are not
serviceable).
E. Refer to Symptom 4.
E. Refer to Symptom 4, Remedy A.
F. Refer to Symptom 7.
F. Refer to Symptom 7, Remedies A and B.
6. Air dryer does not purge or
exhaust air.
A. Faulty air dryer purge valve.
A. After determining air reaches purge valve control port by
installing a T-fi tting with a pressure gauge into the governor
unloader port, repair purge valve if necessary.
B. See Causes B, E, and F for Symptom
#4.
B. Refer to Symptom 4, Remedies B, E, and F.
Also refer to Symptom 1, Remedy B.
7. Desiccant material being
expelled from air dryer purge
valve exhaust (may look like
whitish liquid or paste or
small beads.)
A. Faulty dryer cartridge.
A. Replace the Bendix
®
AD-IS
®
air dryer cartridge or AD-IS air
dryer.
B. Excessive dryer vibration.
B. Check the AD-IS air dryer mounting for looseness or damage.
Repair mounting and replace cartridge.
8. Unsatisfactory desiccant life. A. Excessive system leakage.
A. Refer to Symptom 1, Remedy A.
B. Wrong vehicle application for AD-IS
®
air dryer.
B. Refer to Symptom 2, Remedy C.
C. Compressor passing excessive oil.
C. Check for proper compressor installation; if symptoms
persist, replace compressor. Refer to Bendix Advanced
Troubleshooting Guide for Air Brake Compressor (BW1971).
9. “Pinging” noise excessive
during compressor loaded
cycle.
A. Single cylinder compressor with high
pulse cycles.
A. A slight “pinging” sound may be heard during system build
up when a single cylinder compressor is used. If this sound
is deemed objectionable, it can be reduced substantially by
increasing the discharge line volume.
This can be accomplished by adding a 90 cubic inch (or
larger) reservoir between the compressor and the AD-IS
air
dryer and reservoir system.
10. The air dryer purge piston
c y c l e s r a p i d l y i n t h e
compressor unloaded (non-
compressing) mode.
A. Compressor fails to “unload”.
A. Check air hose from governor to compressor for a missing,
kinked or restricted line. Install or repair air hose.
Repair or replace compressor unloader.
