BENDIX SD-08-2414 manual Air compressor must remain unloaded for a

BENDIX® AD-IP®AIR DRYER TROUBLESHOOTING CHART

SYMPTOMS	CAUSE	REMEDY
2. Water and/or oil in	A. Improper discharge line	A. Refer to Connecting the Air Lines section as well
the supply or service	length or improper line	as Appendix A, Table A columns 1 & 2 then check
reservoir.	material. The maximum air	line size and length.
	dryer inlet temperature is
	exceeded.

B.Air system charged from an B. If the system has an outside air fill provision, outside

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

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