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2

FIGURE 2 - BENDIX

® 

AD-IS

®

 AIR DRYER AND RESERVOIR SYSTEM CHARGE CYCLE 

The Bendix

®

 AD-IS

®

 PuraGuard

®

 oil coalescing air dryer 

has an identical appearance to the standard AD-IS

®

 air 

dryer, but contains a coalescing media at the inlet of the 
desiccant bed.  The coalescing media provides a higher 
level of oil removal over the standard AD-IS air dryer.  
The AD-IS PuraGuard oil coalescing air dryer has all of 
the same functions as the standard AD-IS air dryer and is 
used in applications where lower oil concentration levels 
are required.

Important!

  When servicing, note that standard AD-IS 

air dryers or air dryer cartridges may be serviced with 
PuraGuard oil coalescing air dryers or cartridges, however, 
PuraGuard oil coalescing air dryers or cartridges must only 
be serviced with like replacements.  

Note

: Unless otherwise stated in this manual, AD-IS air 

dryer and reservoir systems refers to both the standard and 
PuraGuard

 

oil coalescing air dryer and reservoir systems.

The function of the pressure protection valves is to protect 
each reservoir from a pressure loss in the other reservoir or 
a pressure loss in an air accessory.  Each of the pressure 
protection valves in the AD-IS

 

air dryer and reservoir 

systems may have different pressure settings. These are 
factory set and must not be changed or adjusted.  

The air dryer and reservoir system consists of a “spin on” 
desiccant cartridge secured to a base assembly.  The 
base assembly contains a delivery check valve assembly, 

COMPRESSOR

GOVERNOR

DESICCANT 

BED

DELIVERY 

CHECK VALVE 

(OPEN)

PRIMARY

PORT (PRI)

PURGE VALVE

(CLOSED)

TURBO 

CUT-OFF 

VALVE

(OPEN)

ENGINE 

TURBO

UNLOADER 

PORT 

SUPPLY 

PORT

PRIMARY

RESERVOIR

PRESSURE 

PROTECTION 

VALVES

AUXILIARY PORTS

(TO ACCESSORIES)

SEE

NOTE 1

Note 1:

The Bendix

®

 AD-IS

® 

air dryer and reservoir system 

purge piston has a purge control channel drain. This 
allows any condensation in this area to fl ow past a 
diaphragm in the top of the purge piston and out 
through a channel in the middle of the central bolt of 
the purge assembly to be drained. During the purge 
cycle this drain is closed.

SAFETY

VALVE

PURGE 

RESERVOIR 

DRAIN VALVE

SECONDARY

RESERVOIR

SECONDARY

PORT (SEC)

PURGE 

RESERVOIR

PURGE 

ORIFICE

OIL COALESCING FILTER 

(BENDIX

®

 AD-IS

®

 PURAGUARD

®

 

OIL COALESCING AIR DRYER)

A

D

C

B

PURGE 

CONTROL 

CHANNEL

DIAGRAM SHOWS ALL PRESSURE 

PROTECTION VALVES OPEN.

Summary of Contents for AD-IS -

Page 1: ...and Reservoir Systems DESICCANT CARTRIDGE PURAGUARD OIL COALESCING SHOWN PURGE RESERVOIR 24 AUX1 AUXILIARY DELIVERY PORTS 4 GOVERNOR PRESSURE PROTECTION VALVES 4 HEATER THERMOSTAT SAFETY VALVE AIR DRY...

Page 2: ...in the other reservoir or a pressure loss in an air accessory Each of the pressure protection valves in the AD IS air dryer and reservoir systems may have different pressure settings These are factor...

Page 3: ...ure that is designed to prevent loss of engine turbo boost pressure during the purge cycle of the Bendix AD IS air dryer and reservoir system For ease of maintenance all replaceable assemblies can be...

Page 4: ...ompressor activating the purge cycle of the air dryer and reservoir The governor unloads the compressor by allowing air pressure to fill the line leading to the compressor unloader mechanism This susp...

Page 5: ...f temperature occurs in one day small amounts of water can temporarily accumulate in the air brake system due to condensation Under these conditions the presence of small amounts of moisture is normal...

Page 6: ...ch in the RUN position check for voltage to the heater and thermostat assembly using a voltmeter or test light Unplug the electrical connector at the air dryer and reservoir system and place the test...

Page 7: ...ll reservoir drain valves 2 Build up system pressure to governor cut out and note that the Bendix AD IS air dryer purges with an audible burst of air followed immediately by approximately 30 seconds o...

Page 8: ...8 FIGURE 7 SPLASH SHIELD BRACKET AND COVER EXPLODED VIEW SPLASH SHIELD BRACKET SPLASH SHIELD COVER LOCK TABS...

Page 9: ...ocation Note that a short puff of trapped air may vent from the safety valve port when removing the valve Install a T fitting into the port Using any adapters necessary reinstall the safety valve in o...

Page 10: ...ot use solvents 3 Inspect for physical damage to the bore and the check valve seat If the bore is damaged by scratches etc that would prevent delivery check valve from seating replace the AD IS air dr...

Page 11: ...governor cut out and allow a full minute for the normal dryer purge cycle to empty the purge reservoir Switch off the engine and fan the brakes so that the system pressure reaches governor cut in The...

Page 12: ...dryer not purging F Refer to Symptom 6 G Purge air exhaust time insufficient due to excessive system leakage G Refer to Symptom 1 3 Safety valve on air dryer popping off or exhausting air A Defective...

Page 13: ...eing expelled from air dryer purge valve exhaust may look like whitish liquid or paste or small beads A Faulty dryer cartridge A Replace the Bendix AD IS air dryer cartridge or AD IS air dryer B Exces...

Page 14: ...14 BW2234 2011 Bendix Commercial Vehicle Systems LLC a member of the Knorr Bremse Group 07 11 All Rights Reserved...

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