IC Bus CE Series 2020, Operation And Maintenance Manual

Page: 212 / 287

Maintenance
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 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
the tank or in the end of the tank. For ease of draining, some or
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.
198