6
Pub. No. OM-A-75 REV. 4 — March 2006
START-UP AND OPERATION
The non-cycling design of the refrigerated dryer assures
proper dew point control at all load conditions. The
refrigerant compressor runs continuously when the dryer is
“ON”. All dryers are installed with fan cycling switches.
These fans will cycle with respect to the load changes,
ambient temperature fluctuations, and the cleanliness of
the condenser. Standard units are designed to operate
under the following conditions:
DESIGN CONDITIONS
1.
Inlet Air Temperature:
100°F design 120°F maximum
2.
Inlet Air Pressure:
100 PSIG design 150 PSIG maximum
3.
Ambient Air Temperature:
55°F minimum 100°F maximum
4.
Cooling Water Temperature:
90°F maximum
5.
Cooling Water Pressure:
35 PSIG minimum 100 PSIG maximum
At temperatures above the 100°F design, refrigeration
capacity will decrease. Operating air pressures below the
100 PSIG design will reduce system capacity.
START-UP PROCEDURE
1.
If the suction pressure gauge reads zero, refrigerant loss
has occurred. Call the factory or distributor for service.
2.
Air dryers with three-phase power supply
are equipped with a compressor crankcase
heater (except scroll compressors). This
heater must be energized by closing the
disconnect switch or circuit breaker a
minimum of 6 to 10 hours before start-up.
Power to the air dryer can be left on to
energize the crankcase heater for the off-
cycle, during evening or weekend
shutdowns.
3.
Check the temperature on the crankcase of the
compressor to make sure the crankcase heater is
working before starting the dryer.
4.
For water-cooled Air Dryers (ADW) make sure the
water supply (Minimum Pressure 35 PSIG) is
available at the condenser inlet. The water
regulating valve will modulate and control the water
flow with respect to the dryer load conditions. The
water-cooled condenser drain plug (located inside
enclosure) must be installed.
5.
For open frame design units [Models AD(W)-1500 &
larger], the following valves
must be open
prior to
start-up. All valves are tagged with specific
instructions.
a. Compressor isolation valves (suction & discharge
service valves).
b. Receiver valve(s) (air-cooled models only).
c. Condenser outlet liquid line valve (water-cooled
models only).
STARTING THE DRYER WITHOUT ENERGIZING
THE CRANKCASE HEATER WILL CAUSE PREMA-
TURE FAILURES OF THE REFRIGERANT COM-
PRESSOR. Failure to comply with procedure of
energizing crankcase heater before start-up
may void warranty.
CRANKCASE HEATER
Air dryers with three-phase power supply
are equipped with a compressor crankcase
heater. This heater must be energized by
closing the disconnect switch a minimum of
6 to 10 hours before start-up. Power to the
air dryer can be left on to energize the
crankcase heater for off-cycle, during
evening or weekend shutdowns (except
scroll compressors).
