21
AD-SP
™
AIR DRYER TROUBLESHOOTING CHART (Continued)
SYMPTOMS
CAUSE
REMEDY
A. Repair or replace air dryer purge valve.
B. One or both dash air gauges should show higher
than normal air pressure. Test compressor
unloader mechanism for proper operation. Repair
or replace unloaders as necessary.
C. One or both dash air gauges may show higher
than normal air pressure. Test governor for proper
operation. Repair or replace as necessary.
D. Kinked, plugged, damaged hose tubing or fittings:
Check to determine if air is reaching first
reservoir. Inspect for kinked tubing or hose.
Check for un-drilled or restricted hose or tubing
fittings. Repair or replace as necessary.
Desiccant cartridge plugged: Check compressor
for excessive oil passing and/or correct
compressor installation. Repair or replace as
necessary. Replace desiccant cartridge.
E. Increase volume in discharge line by added length
or size of line, or add a ping tank.
4. Air is escaping from air
dryer exhaust during
Charge Cycle but able
to build system air
pressure. (Compressor
pumping.)
A. Air dryer purge valve
leaking.
B. Compressor unloader
mechanism malfunction.
C. Governor malfunction.
D. Air flow to the supply
reservoir restricted.
E. Excessive pressure
pulsations from
compressor. (Typical
single cylinder type.)
A. Air dryers remove water and oil from the air
brake charging system. A small amount of oil is
normal. Check that regular maintenance is
being performed and that the amount of oil in the
air tanks (reservoirs) is within the acceptable
range shown on the BASIC cup (see also
column 5 of Appendix A, Table A). Replace the
air dryer cartridge as needed and return the
vehicle to service.
A. Air brake charging
system is functioning
normally.
3. Oil present at air dryer
purge exhaust or
cartridge during
maintenance.
5. Air escaping from air
dryer exhaust port
during entire purge
cycle. (Compressor not
running.)
A. Leaking turbo cutoff valve
in AD-SP
™
air dryer.
B. Leaking purge piston
o-ring in AD-SP
™
air
dryer.
C. Leaking or
malfunctioning purge
control mechanism.
D. Leaking delivery check
valve.
A. Note dash gauges to verify Purge Cycle has
ended. Perform Air Dryer “Operation & Leakage
Tests” specified in this manual. Repair or replace
as necessary.
B. Perform Air Dryer “Operation & Leakage Tests”
specified in this manual. Repair or replace as
necessary.
C. Replace AD-SP
™
air dryer.
D. Perform Air Dryer “Operation & Leakage Tests”
specified in this manual. Repair or replace as
necessary.
