Bendix Commercial Vehicle Systems AD-IS AIR DRYER AND RESERVOIR SYSTM - Manual (Page 8)

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Warm the thermostat and heater assembly to
approximately 90° F and again check the resistance.
The resistance should exceed 1000 ohms. If the
resistance values obtained are within the stated
limits, the thermostat and heater assembly is
operating properly. If the resistance values obtained
are outside the stated limits, replace the heater and
thermostat assembly.
6. Pressure Protection Valves. Observe the pressure
gauges of the vehicle as system pressure builds from
zero. The primary or secondary gauge should rise until
it reaches approximately 106 psi (±6 psi), then level
off (or a momentary slight fall) as the next pressure
protection valve opens—supplying its reservoir. When
that pressure gauge passes through approximately 106
psi (±6 psi) there should be an associated leveling off (or
momentary slight fall) of pressure as the third and fourth
pressure protection valves open. Then the primary and
secondary gauges should increase together until they
reach their full pressure of approximately 130 psi (±5
psi).
If the Bendix ® AD-IS ® air dryer and reservoir system does
not perform within the pressure ranges as described
above, recheck using gauges known to be accurate.
If the readings remain outside of the ranges outlined,
replace the AD-IS air dryer and reservoir system.
NOTE: There are no kits available for the servicing
of the pressure protection valves. Warning: Do not
attempt to adjust or service the pressure protection
valves—incorrect pressure protection valve settings
can result in automatic application of the vehicle spring
brakes without prior warning (in the event one of the
supply circuits experiences rapid pressure loss).
GENERAL
When rebuilding or replacing components of the air dryer
and reservoir, use only genuine Bendix ® brand replacement
parts. For ease in servicing, the AD-IS air dryer and
reservoir have been designed so that maintenance kits can
be installed without removing the air dryer and reservoir
from the vehicle. CAUTION: Always depressurize the air
dryer and purge reservoir—and all other reservoirs on the
vehicle—to 0 psi before servicing the air dryer.
If—after completing the routine operation and leakage
tests—it has been determined that one or more components
of the air dryer requires replacement or maintenance, refer
to the Maintenance Kit listing shown in this manual or the
Bendix ® Quick Reference Catalog for the appropriate kit(s).
The Quick Reference catalog (BW1114) can be ordered
and viewed on line at
www.bendix.com.
Note: Kits are not available for the servicing of the pressure
protection valves (See Figure 5). Do not attempt to adjust
or service the pressure protection valves - these are not
service items.
TESTING THE BENDIX ® AD-IS ® AIR DRYER
AND RESERVOIR SYSTEM
Before placing the vehicle into service, perform the
following tests:
1. Close all 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 of air flowing out of the purge valve.
3. Apply and release the service brakes to reduce system
air pressure to governor cut-in. Note that the system
once again builds to full pressure and is followed by a
purge at the air dryer exhaust.
4. It is recommended that the total air system be tested for
leakage to assure that the AD-IS air dryer and reservoir
system will not cycle excessively.
FIGURE 5 - PRESSURE PROTECTION VALVE LOCATIONS
PRESSURE
PROTECTION
VALVE
LOCATIONS
THE BENDIX ® AD-IS ®
AIR DRYER GOVERNORS ARE
NON-ADJUSTABLE
AND FEATURES A BREATHER
VALVE IN THIS PORT
WARNING
DO NOT ATTEMPT TO ADJUST OR
SERVICE THE PRESSURE PROTECTION
VALVES. INCORRECT PRESSURE
PROTECTION VALVE SETTINGS CAN
RESULT IN AUTOMATIC APPLICATION
OF VEHICLE SPRING BRAKES WITHOUT
PRIOR WARNING.