Dryer Manual

AIR DRYER INSTRUCTION MANUAL
13
TROUBLESHOOTING
Problem Possible Cause Repair Comments
Dryer not running. No
Power
Power failure Check power to unit
Faulty wiring, loose
terminals
Request assistance from a
qualified electrician or
refrigeration contractor.
Magnetic contactor
damage
Have contactor checked by
a qualified electrician or
refrigeration contractor &
replace contactor if
necessary
Dryer-on light is lit
but fan is not running.
Fan automatically runs
if refrigerant high
pressure reaches upper
set point.
Check amount of
refrigerant.
Fan operates automatically to
keep refrigerant pressure
below the high pressure switch
setting. The fan can stop if
pressure is under the
recommended pressure setting.
Check that fan blades are
free to move.
Check fan pressure switch.
Check voltage to fan
motor and faulty fan
Excessive
compressed air inlet
temperature.
Be sure that dryer is
working in temperatures
lower than design
conditions.
See data plate for ambient
temperature setting.
The dryer should be working
within designed specifications
(see description in this
manual). If conditions are
exceeded, the dryer overworks,
dew point goes up and
protecting switches turn off.
Excessive vibration
and mechanical noise.
Compressor is
slugging (liquid
refrigerant shock) at
start- up.
Be sure to preheat the dryer
at least 4 hours for dryers
equipped with a crankcase
heater.
Refrigerant may move
between receivers when
refrigerant compressor is
stopped and not heated,
especially if stopped for a long
time. This migration may
cause liquid shock (slugging)
in valves especially on large
dryers containing more
refrigerant.
Compressor sounds
abnormal
Check compressor and
replace if necessary
Noisy thermostatic
expansion valve
Check refrigerant capacity
and replace filter
Evaporate pressure
too low
Refrigerant leak Repair leak and add
refrigerant
Evaporate pressure
too high
Thermostatic
expansion valve
opened too much
Adjust thermostatic
expansion valve to proper
setting
Faulty thermostatic
expansion valve
Replace thermostatic
expansion valve
Condense pressure too
low
Fan motor switch not
set properly
Set fan switch properly