BENDIX BW1450 manual Preventative Maintenance Section

AD-4™AIR DRYER TROUBLESHOOTING CHART (Continued)

SYMPTOMS	CAUSE	REMEDY
	F. Governor malfunction.	F. Test governor operation and/or inspect the
	Missing or restricted	control line leading from the governor UNL
	governor control line	(unloader) port to the air dryer control port.
	installation.
5. Constant exhaust of air	A. Air dryer purge valve	A. With compressor loaded, apply soap solution
at air dryer purge valve	leaking excessively.	on purge valve exhaust, to test for excessive
exhaust. (Charge		leakage. Repair purge valve as necessary.
mode.)
	B. Compressor fails to	B. Confirm failure to unload by increasing &
	unload (stop	decreasing engine RPM and noting change in
	compressing air) and air	the rate of leakage and intensity of
	dryer purge exhaust	accompanying leakage sound. Repair/replace
	makes “sputtering” or	compressor unloaders.
	“popping” sound.
	C. Purge control line	C. Purge control line must be connected to
	connected to reservoir or	unloader port of governor.
	exhaust port of governor.
	D. Purge valve frozen open -	D. Test heater and thermostat as described in
	malfunctioning heater	Preventative Maintenance Section.
	and thermostat, wiring,
	blown fuse.
	E. Excessive system	E. See Symptom #1.
	leakage.
	F. Purge valve stays open -	F. Repair purge valve and housing.
	supply air leaks to
	control side.
6. Can not build system air	A. Inlet and outlet air	A. Connect compressor discharge to air dryer
pressure.	connections reversed.	supply port. Reconnect lines properly.
	B. Check valve between air	B. Test check valve for proper operation. Repair or
	dryer and first reservoir.	replace as necessary.
	C. Kinked or blocked	C. Check to determine if air passes through
	(plugged) discharge line.	discharge line. Check for kinks, bends,
		excessive carbon deposits, or ice blockage.
	D. Excessive bends in	D. Discharge line should be constantly sloping from
	discharge line (water	compressor to air dryer with as few bends as
	collects and freezes).	possible.
	E. Refer to Symptom 4,	E. Refer to Symptom #4, Remedies E & F.
	causes E & F.
7. Air dryer does not purge	A. Missing, broken, kinked,	A. Inspect control line from governor UNL (unloader)
or exhaust air.	frozen, plugged or	port to control port of air dryer. Test to determine
	disconnected purge	air flows through purge control line when
	control line.	compressor unloaded. Check for undrilled
		fittings. (See Symptom #4, Remedy C.)
	B. Faulty air dryer purge	B. After determining air reaches purge valve
	valve.	(Remedy A above), repair purge valve.
	C. See Causes, B, E, G for	C. Refer to Remedies B, E, G for Symptom #4.
	Symptom #4.

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