14
BENDIX
®
AD-IS
®
AIR DRYER & RESERVOIR SYSTEM
TROUBLESHOOTING CHART
SYMPTOM
CAUSE
REMEDY
2. Water in the vehicle
reservoirs.
A. Maximum air dryer inlet temperature is
exceeded due to improper discharge
line length.
A. Check for excessive carbon build-up in the compressor
discharge line. Replace if required. Make certain that the
discharge line length is at least 6 ft. Increase the discharge line
length and/or diameter to reduce air dryer inlet temperature.
B. Air system charged from outside
air source (outside air not passing
through the air dryer).
B. If the system must have an outside air fill provision, the outside
air should pass through the air dryer.
C. Excessive air usage – Air dryer not
compatible with the vehicle air system
requirement (Improper air dryer/
vehicle application).
C. Refer to the Bendix Advanced Troubleshooting Guide for Air
Brake Compressors (BW1971) for proper application of the
Bendix
®
AD-IS
®
air dryer & reservoir system. An extended
purge model (Bendix
®
AD-IS
®
EP) is available for many higher
air usage vehicles, such as city buses and construction
vehicles.
If the vehicle is equipped with high air usage accessories,
such as trailer pump-off systems or central tire inflation, the
air for these accessories must by-pass the dryer reservoir
system.
D. Desiccant requires replacement.
D. Replace the desiccant cartridge assembly.
E. Air by-passes desiccant cartridge
assembly.
E. If the vehicle uses a Holset
®
compressor, inspect the feedback
check valve for proper installation and operation.
F. Air dryer not purging.
F.
Refer to Symptom 6.
G. Purge (air exhaust) time is insufficient
due to excessive system leakage.
G.
Refer to Symptom 1.
3. Safety valve on the air
dryer is “popping off” or
exhausting air.
A. Defective AD-IS air dryer & reservoir
system delivery check valve.
A. Test to determine if air is passing through the check valve.
Repair or replace.
Refer to Symptom 1, Remedy B.
B. Safety valve setting too low (<150 psi) B. Replace the safety valve.
C. System pressure too high (>135 psi) C. Test with an accurate gauge. Replace the governor if
necessary.
D. Excessive pressure pulsations from
compressor. (Typical single cylinder
type).
D. Increase volume in discharge line. This can be accomplished
by adding a 90 cubic inch (or larger) reservoir between the
compressor and the AD-IS air dryer & reservoir system.
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.
B. Purge valve frozen open – faulty heater
and thermostat, wiring, or blown fuse.
B.
Refer to paragraph 5 of the Operation and Leakage Tests
for the heater and thermostat test.
C. Defective Bendix
®
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.
Summary of Contents for SD-08-2418
Page 12: ...12 NOTES...
