Bendix Commercial Vehicle Systems AD-IS AIR DRYER AND RESERVOIR SYSTM - Manual (Page 15)

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BENDIX ® AD-IS ® AIR DRYER AND RESERVOIR SYSTEM
TROUBLESHOOTING CHART
SYMPTOM CAUSE REMEDY
4. Constant exhaust of air at the
air dryer purge valve exhaust
or unable to build system
pressure. (Charge mode.)
A. Air dryer purge valve leaking
excessively.
A. With the compressor loaded, apply a soap solution on the
purge valve exhaust, to test for excessive leakage. Repair
or replace the purge valve as necessary.
Refer to Technical Bulletin TCH-008-040.
B. Purge valve frozen open - faulty heater
and thermostat, wiring, blown fuse.
B. Refer to paragraph 5 of the Operation and Leakage Tests for
the heater and thermostat test.
C. Defective AD-IS air dryer delivery
check valve.
C. Refer to Symptom 1, Remedy B.
D. Leaking Turbo Cut-Off valve. D. Repair or replace the purge valve assembly.
E. Defective governor. E. Check the governor at both “cut-in” and “cut-out” positions
for (i) proper pressures and (ii) excessive leakage at fittings
and exhaust.
F. Leaking purge valve control piston
seals.
F. Repair or replace the purge valve assembly.
5. Cannot build system air
pressure.
A. Supply pressure to the air dryer is not
sufficient.
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-fitting 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 the 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 the mounting and replace cartridge.
8. Unsatisfactory desiccant life. A. Excessive system leakage. A. Refer to Symptom 1, Remedy A.
B. Wrong vehicle application for an
AD-IS ® air dryer.
B. Refer to Symptom 2, Remedy C.
C. Compressor passing excessive oil. C. Check for proper compressor installation; if the symptoms
persist, replace the compressor. Refer to Bendix Advanced
Troubleshooting Guide for Air Brake Compressor (BW1971).