BENDIX SD-08-2403 Manuale Utente

BW1597 © 2004 Bendix Commercial Vehicle Systems LLC All rights reserved.  7/2004 Printed in U.S.A.

4. Constant exhaust of air

A.

Air dryer purge valve leaking

A.

With compressor loaded,  apply soap solution

at air dryer purge valve

excessively.

on  purge valve exhaust, to test for excessive

exhaust or unable to

leakage. Repair purge valve as necessary.

build system pressure.

B.

 Defective governor.

B.

Check governor for proper “cut-in”, “cut-out”
pressure and excessive leakage in both
positions. Repair or replace as necessary.

C.

Purge control line connected to

C.

Purge control line must be connected to

reservoir or exhaust port of governor.

unloader port of governor.

D.

 Purge valve frozen open - faulty

D.

Test heater and thermostat as described in

heater and thermostat, wiring, blown

Step 7 of Preventive Maintenance Section.

fuse.

E.

Inlet and outlet air connections

E.

Compressor discharge to inlet port. Reconnect

reversed.

lines properly.

F.

Check valve between air dryer and first

F.

Test check valve for proper operation (see

reservoir defective.

Symptom #3, Remedy B).

G.

Kinked or blocked (plugged)

G.

Check to determine if air passes through

discharge line.

discharge line. Check for kinks, bends,
excessive carbon deposits.

H.

Excessive bends in discharge line

H.

Discharge line should be constantly sloping

(water collects and freezes).

from compressor to air dryer with as few bends
as possible.

I.

Excessive  system  leakage.

I.

See Symptom #1’s Causes and Remedies.

5. Air dryer does not purge

A.

Broken, kinked, frozen, plugged or

A.

Test to determine air flows through purge

or exhaust air.

disconnected purge control line.

control line when compressor unloaded. Check
for undrilled fittings. (See Symptom #4,
Remedy C.)

B.

Faulty air dryer purge valve.

B.

After determining air reaches purge valve
(Remedy A above), repair purge valve.

C.

See Causes B,E,F,G,H, for Symptom

C.

Refer to Remedies B, E, F, G, H, for Symptom

#4.

#4.

6. Desiccant material being

A.

This symptom is almost always

A.

See Causes and Remedies for Symptoms 1,2,3,4

expelled from air dryer

accompanied by one or more of

and 5.

purge  valve  exhaust

Symptoms 1,2,3,4 and 5. See related

(may look like whitish

causes for these Symptoms above.

liquid or paste or small
beads).

B.

Air  dryer  not  securely  mounted.

B.

Vibration should be held to minimum. Add

(Excessive vibration).

bracket supports or change air dryer mounting
location if necessary.

OR

Unsatisfactory desiccant

C.

Defective cloth covered perforated

C.

Replace or rebuild desiccant cartridge. NOTE:

life.

plate in air dryer desiccant cartridge

If rebuilding cartridge, carefully follow

or improperly rebuilt desiccant

instructions packed with cartridge

rebuild kit.

cartridge.

D.

Compressor  passing  excessive  oil.

D.

Check for proper compressor installation; if
symptoms persist, replace compressor.

E.

Faulty heater and thermostat, wiring,

E.

Refer to Remedy D under Symptom #4.

fuse not allowing purge. (Cold weather
operation only.)

7. Unable to remove end

A.

Result of reversing the inlet and outlet

A.

Refer to Symptom #4, Cause E.

cover, or unable to install

connections. (See Symptom #4,

new desiccant cartridge.

Cause E.)

8. Air dryer end cover

A.

Excessive  system  pressure  build  up

A.

Because it is difficult to determine extent of

separates  from  air  dryer

within air dryer; caused by either

internal damage to air dryer, it is recommended

housing during operation.

plugged desiccant, check valve failure,

that the air dryer be replaced.

frozen or obstructed discharge line
(between air dryer and first reservoir) or

NOTE: This type of failure can be prevented by

governor failure in conjunction with

checking the dryer for proper operation every

safety valve failure.

three (3) months.