Air Dryer; Air Dryer Desiccant Replacement; Air Dryer Purge Valve; Air Dryer Heater - IC Bus CE Series Operation And Maintenance Manual

Air Dryer

The function of the air dryer is to collect and remove moisture
and contaminants before the compressed air reaches the air
reservoirs. This protects the air system components from
malfunctioning including blockage, corrosion, and freezing.
For air tank draining requirements, refer to the Maintenance
Instructions section as well as local regulations.
The air dryer is installed in the discharge line between the air
compressor and the air system reservoirs. The air dryer includes
a replaceable desiccant cartridge and oil blocking filter that is
periodically serviced. It also may include a heater to prevent the
discharge valve from freezing in cold weather.

Air Dryer Desiccant Replacement

Open reservoir drain valves and check for presence of water.
Small amounts of water due to condensation is normal. If the
wet (air) tank and primary or secondary tanks are collecting an
abnormally high amount of water between regular air tank drain
intervals, replace the air dryer desiccant.
The air dryer desiccant replacement interval may vary; it is
generally recommended that the desiccant be replaced every 12
months for small air dryers like the Bendix AD-IP
months for large air dryers like the Bendix AD-9
has shown that extended or shortened life has resulted for a
particular installation, then the interval should be increased or
reduced accordingly.

Air Dryer Purge Valve

Check that the purge valve opens and expels moisture when
the air governor shuts off the air compressor. Air should escape
rapidly and then quickly stop. If the purge valve does not open,
or you can hear a slight audible air leakage past the valve for
longer than 30 seconds, the valve may be sticking and should
be rebuilt. Purge valves may also stick if the air dryer heater has
failed and ice is clogging the valve.

Air Dryer Heater

Check that the air dryer heater activates at temperatures below
freezing. With the vehicle in a cold environment and before the
engine is started, turn on the ignition and touch the air dryer
housing. It should be warmer than other metallic items on the
vehicle. If some warmth cannot be felt it, may indicate that the
heater element or the wiring powering it should be serviced.

Air Reservoir / Tanks Moisture Draining

Moisture taken in with the air through the compressor inlet valves
collects in the reservoirs. Drain the wet tank reservoir every day
at the end of the trip. Drain the primary and secondary tanks
periodically. Open the drain cock located either on the bottom of
® , or every 24
the tank or in the end of the tank. For ease of draining, some or
® . If experience
all tanks may be equipped with optional pull cords. There must
be some air pressure in the system to ensure proper drainage.
Close the drain cocks after all moisture has been expelled. If
you are unsure which tank is the wet tank, drain all tanks daily.
On vehicles equipped with automatic drain valve(s), moisture
and contaminants are automatically removed from the reservoir
Maintenance
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