CHASSIS INFORMATION — 10
218
2008 IMPERIAL
NOTE:
If an excessive amount of water is
present when performing the monthly
air tank drain service, the filter for the
air dryer may need to be changed.
Desiccant-Type Air Dryer
1. Warm, humid air from the compressor
condenses into either water or water
vapor before entering the air dryer.
2. A desiccant-type air dryer protects the
motorhome air brake system by drying
moisture-laden air before it passes
through the air reservoirs and into the
brake system.
3. Water collects in the base of the dryer
when warm air condenses the water
before it enters the dryer, or inside of
the dryer before the water reaches the
desiccant.
4. The desiccant material then removes
additional water vapor, further drying
the air.
5. During regeneration phase, the
regeneration valve and pressure-
controlled check valve remove water
from the desiccant bed with a back
fl
ow
of dried, expanded system air.
Air Dryer Cycle
The governor turns the compressor on when
the supply tank pressure drops below cut-in
pressure. Compressed air passes into the air
dryer at the inlet port:
1. Moisture-laden air and contaminants
pass through the desiccant.
2. Moisture is retained by the desiccant.
Moisture also collects in the base of
the dryer.
3. The governor turns the compressor
off when the system reaches cutout
pressure (approximately 145 psi).
4. The dryer purges and expels water
collected in the dryer base.
5. When the regeneration valve opens, the
dry system air
fl
ows back through the
dryer. A small charge of air from the
front air tank back
fl
ows through the
fi
lter. The back
fl
ow dries the desiccant,
preparing it for the next cycle.
AIR SPRING INSPECTIONS
Items listed below should be checked when
the motorhome is in for periodic maintenance.
NOTE:
Never attempt to service the air
suspension on a motorhome with the air
spring inflated.
REPLACEMENT REQUIREMENTS
Components
When to replace?
Why?
Desiccant Cartridge
•
Every two to three years.
•
When compressor is
replaced.
•
Water in supply tank.
•
Preventive maintenance.
•
Contaminated cartridge.
•
Saturated or contaminated
cartridge, high duty cycle
(wrong application of air dryer).
1. O-Ring
2. Seal Seat
3. Cartridge Seal
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