BENDIX SD-08-2418 manual Symptom Cause Remedy

BENDIX®AD-IS®AIR DRYER AND RESERVOIR SYSTEM

TROUBLESHOOTING CHART

SYMPTOM		CAUSE		REMEDY
1. Dryer is constantly “cycling” A.		Excessive system leakage.	A.	Test for excessive system leakage. Allowable leakage
or purging.				observed at the dash gauge:
				- Single vehicle - 1 psi/minute.
				- Tractor trailer - 3 psi/minute.
				Using a Bensoap solution, test vehicle for leakage at the
				fittings, drain valves and system valves and any accessories
				(i.e. air suspension) connected to the Bendix® AD-IS®air dryer
				auxiliary ports. If an accessory is suspected to be the cause
				of leakage, disconnect that accessory from the air dryer, plug
				the auxiliary port that it was in, and retest the AD-IS air dryer
				for proper purge cycling. Repair or replace as necessary.
	B.	Defective delivery check valve.	B.	Build system pressure to governor cut-out. Wait 1 minute for
				the completion of the purge cycle. Using a soap solution at
				the exhaust of the purge valve, leakage should not exceed
				a one inch bubble in less than 5 seconds.
				If a rapid loss of pressure is found, the following procedure
				will determine if the delivery check valve is malfunctioning:
				Build system pressure to governor cut-out and allow a full
				minute for the normal dryer purge cycle to empty the purge
				reservoir. Switch off the engine and apply and release the
				brakes so that the system pressure reaches governor cut-in.
				The purge valve will return to its closed position. The purge
				reservoir has a drain valve which is opened by moving the
				center lever away from its closed position. Open the drain
				valve and wait 10 seconds to allow any residual purge
				pressure to be released. Release the lever, closing the drain
				valve. Carefully remove the air dryer cartridge using a strap
				wrench and then test for air leaking through the center of
				the threaded boss by applying a soap solution to the area.
				Replace the delivery check valve if there is excessive leakage
				(exceeding a one inch bubble in five 5 seconds).
				Re-grease the seal on the air dryer cartridge before
				reinstalling. Be sure the drain valve on the purge reservoir
				is not leaking before restoring vehicle to service.
	C.	Defective governor.	C.	Check the governor at both the “cut-in” and “cut-out” position
				for (i) proper pressures and (ii) excessive leakage at fittings
				and exhaust.

D.Compressor unloader mechanism D. Remove the air strainer, or fitting, from compressor inlet

leaking excessively.	cavity. With the compressor unloaded, check for unloader
	piston leakage. Slight leakage is permissible.

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