SYSTEM CHARGE SEQUENCE
The Bendix®DRM™module has an integrated reservoir,
air dryer and valve system. This means that when the air
pressure in the system builds from zero, the order in which
the reservoirs fill is much different than a traditional three(3)
reservoir system. Observe the pressure gauges of the
vehicle as system pressure builds from 0 psi. The primary
reservoir gauge rises until it reaches about 110 psi, then
the secondary reservoir begins to build. As the secondary
reservoir builds initial pressure to approximately 55 psi –
then to approximately 85 psi – a sequence of two pressure
protection valves open, supplying vehicle accessories. At
about110 psi, both primary and secondary reservoirs charge,
simultaneously, until governor cut-out is reached.
BRAKE CIRCUIT PROTECTION
The Bendix®AD-IS®air dryer design innovations allow the
system to maintain one brake circuit, up to about 100 psi,
even if there is a pressure loss in the other brake circuit. For
example, when one reservoir drain cock is opened, initially
both reservoir gauges will fall; however, the AD-IS®dryer’s
pressureprotectionvalveswill close at pressures atorabove
70 psi, protecting the remaining brake circuit from further
loss of pressure.
ROADSIDE INSPECTIONS
As outlined above, the Bendix® AD-IS®air dryer design
advancements mean that, in the event of a roadside
inspection, the system behavior includes: When the system
ischargedtogovernor cut-out – and thenwhenonereservoir
draincock is opened – initially both reservoir gaugeswill fall.
The AD-IS®air dryer pressure protection valves, however,
will close at pressures at or above 70 psi, protecting the
remaining brake circuit from further loss of pressure.
IMPORTANT SYSTEM PERFORMANCE NOTES
Congratulations, your new vehicle is equipped
with a Bendix®Dryer Reservoir Module (DRM™)
featuring a Bendix®AD-IS®Air Dryer.
MAINTENANCE INTERVALS
In general, we recommend that maintenance checks be
made every 900 operating hours; 25,000 miles; or three(3)
months, whichever comes first (see warranty publication
BW1715for details). Important: Review the warranty policy
before performing any intrusive maintenance procedures.
Because no two vehicles operate under identical conditions,
maintenanceandmaintenanceintervalswillvary. Experience
is a valuable guide in determining the best maintenance
interval for any one particular operation. See the Service
Data Manual for more information (SD-98-9808).
TAG WARRANTY
The Bendix® Total Air Guarantee (TAG) limited warranty
covers Bendix air system components installed as original
equipment on the vehicle for three(3) years or 350,000
miles. See Warranty (publication BW1716) for full details –
restrictions apply.
BW1980 © 2010 Bendix Commercial Vehicle Systems LLC, a member of the Knorr-Bremse Group • All Rights Reserved • 6/2010
DESICCANT
CARTRIDGE
SECONDARY
RESERVOIR
AD-IS®
AIR DRYER
INTEGRATED PURGE
RESERVOIR
GOVERNOR
PRESSURE
PROTECTION
VALVES
HEATER/
THERMOSTAT
SAFETY
VALVE
Printed on recycled paper
