Bendix Commercial Vehicle Systems AD-9 AND AD-9 IPC AIR DRYERS 4/11 - Manual (Page 22)

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Bendix ® AD-9 ® AND AD-9 ® IPC AIR DRYER TROUBLESHOOTING CHART
SYMPTOMS CAUSE REMEDY
2. Water and/or Oil in Supply or
Service Reservoir.
A. Desiccant requires replacement
- excessive contaminants in
desiccant cartridge assembly.
A. Replace desiccant cartridge.
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. Air system charged from outside
air source (outside air not passing
through air dryer)
C. If system must have outside air fi ll provision, outside air should
pass through the air dryer. This practice should be minimized.
D. Air dryer not purging (see
Symptom #5).
D. See Symptom #5.
E. Purge (air exhaust) time insuffi cient
due to excessive system leakage
(see causes for Symptom #1).
E. Check causes and remedies for Symptom #1.
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
fi ttings, connections, lines, chambers or
valves, etc.
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 - Bendix ® AD-9 ® and AD-9 ® IPC air dryers
are 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.