Bendix Commercial Vehicle Systems AD-IS AIR DRYER AND RESERVOIR SYSTM - Manual (Page 14)

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BENDIX ® AD-IS ® AIR DRYER AND 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 air dryer).
B. If system must have outside air fill provision, outside air should
pass through 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 and 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 and reservoir
system delivery check valve.
A. Test to determine if air is passing through check valve. Repair
or replace. Refer to Symptom 1, Remedy B.
B. Safety valve setting too low (<150 p.s.i.) B. Replace the safety valve.
C. System pressure too high (>135 p.s.i.) 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 and reservoir system.