Service manual

17
2. Water in vehicle
reservoir.
A. Desiccant requires
replacement - excessive
contaminants in
desiccant cartridge
assembly.
B. Improper discharge line
length or improper line
material. Maximum air
dryer inlet temperature is
exceeded.
B. Refer to section entitled “Connecting the Air
Lines” as well as Appendix A, Table A columns
1 & 2 then check line size and length.
C. If system must have outside air fill provision,
outside air should pass through air dryer. This
practice should be minimized.
D. See Symptom #5.
E. Check causes and remedies for Symptom #1.
F. See Appendix A, Table A, column 1, for
recommended compressor sizes. If the
compressor is “too small” for the vehicle vocation
(for example, where a vehicle’s vocation has
changed or service conditions exceed the original
vehicle or engine OE spec’s) then upgrade the
compressor. Note: The costs incurred (e.g.
installing a larger capacity compressor, etc.) are
not covered under original compressor warranty.
Charge Cycle Time - The AD-9
™
air dryer is
designed to provide clean, dry air for the brake
system. When a vehicle’s air system is used to
operate non-brake air accessories it is necessary
to determine that during normal, daily operation
the compressor should recover from governor
“cut-in” to governor “cut-out” (usually 100 psi to
120 psi) in 90 seconds or less at engine RPM’s
commensurate with the vehicle vocation. If the
recovery time consistently exceeds this limit, it
may be necessary to “bypass” the air accessory
responsible for the high air usage. An example of
where a by-pass system would be required is
when the compressor is used to pressurize a
tank trailer for purposes of off-loading product.
Consult your local authorized Bendix parts outlet
or sales representative for additional information.
A. Replace desiccant cartridge.
E. Purge (air exhaust) time
insufficient due to
excessive system
leakage (see causes for
Symptom #1).
C. Air system charged from
outside air source
(outside air not passing
through air dryer).
D. Air dryer not purging
(see Symptom #5).
AD-9
™
AIR DRYER TROUBLESHOOTING CHART
SYMPTOMS CAUSE
REMEDY
F. Excessive air usage,
duty cycle too high - Air
dryer not compatible
with vehicle air system
requirement (Improper air
dryer/vehicle
application).
NOTE: Duty Cycle is the
ratio of time the compressor
spends building air to total
engine running time. Air
compressors are designed
to build air (run “loaded”) up
to 25% of the time. Higher
duty cycles cause
conditions that affect air
brake charging system
performance which may
require additional
maintenance. Factors that
add to the duty cycle are: air
suspension, additional air
accessories, use of an
undersized compressor,
frequent stops, excessive
leakage from fittings,
connections, lines,
chambers or valves, etc.
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