Bendix Commercial Vehicle Systems AD-RP PuraGuard Oil Coalescing Remote Purge Air Dryers - Manual (Page 19)

19
Bendix ® AD-RP ™ AIR DRYER TROUBLESHOOTING CHART
SYMPTOMS CAUSE REMEDY
2. Water and/or oil in
supply or service
reservoir. (continued)
E. Excessive air usage, duty
cycle is too high; the air
dryer is not compatible
with the 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.
E. See A ppendix A / Table A /c olumn 1 for the
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 specs), then upgrade the compressor. Note:
The costs incurred (e.g. installing a larger capacity
compressor, etc.) are not covered under the original
compressor warranty.
Charge Cycle Time - The Bendix ® AD-RP ™ 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, 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 RPMs commensurate with the
vehicle vocation. If the recovery time consistently
exceeds this limit, it may be necessary to “by-pass”
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.
Purge Cycle Time - During normal vehicle operation,
the air compressor must remain unloaded for a
minimum of 30 seconds. This minimum purge time
is required to ensure complete regeneration of the
desiccant material. If the purge time is consistently
less than the minimum, an accessory bypass system
must be installed. Consult your local authorized
Bendix parts outlet or sales representative for
additional information.
Air Compressor Size - The AD-RP air dryer was
designed primarily for use with compressors rated up
to 30 CFM. Contact an authorized Bendix parts outlet
or a Bendix sales representative for assistance when
using the AD-RP dryer with a compressor which has
a rated displacement exceeding 30 CFM.
(continued)