AD-IPAIR DRYER TROUBLESHOOTING CHART (Continued)

SYMPTOMS

CAUSE

REMEDY

4. Safety valve on air dryer

F. Governor malfunction.

F. Test governor operation and/or inspect the

“popping off” or

Missing or restricted

control line leading from the governor UNL

exhausting air

governor control line

(unloader) port to the air dryer control port.

(continued).

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. Refer to Technical Bulletin

mode.)

 

TCH-008-040. Repair purge valve as necessary.

 

B. Compressor fails to

B. Confirm failure to unload by increasing &

 

unload (stop compressing

decreasing engine RPM and noting change in

 

air) and air dryer purge

the rate of leakage and intensity of

 

exhaust makes

accompanying leakage sound. Repair/replace

 

“sputtering” or “popping”

compressor unloaders.

 

sound.

 

 

C. Purge control line

C. Purge control line must be connected to

 

connected to reservoir

unloader port of governor.

 

or 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

if 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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BENDIX BW1811 manual Preventative Maintenance Section