19
Unit Cooler troubleshooting.
Symptoms
Possible causes
Solution
Cooling is
insufficient.
(Room
temperature too
high.)
Insufficient refrigerant
Add refrigerant
Too much oil in unit cooler
Check the easy oil return in
suction line.
Superheat too high
Adjust expansion valve.
Room thermostat set too high
Adjust thermostat
Coil iced-up
Manually defrost coil. Check
defrost time, period, controls.
Defective distributor
Replace.
Uneven coil
frosting.
Defective distributor
Replace
Defective heater
Replace
Defrost termination set too low
Adjust defrost termination setting
higher
and
move
defrost
thermostat.
Ice build up in
coil quickly
Fin spaced too narrow
Replace coil
Evaporating temperature too low
Adjust expansion valve
Decrease of air volume
Check fan and clean air filter
Unit cooler capacity is too small
Replace unit cooler
Fan not
operating
Main switch open
Close switch
Blown fuses
Replace fuses. Check for short
circuits or overload conditions
Defective motor
Replace motor
Defective
timer
or
defrost
thermostat
Replace defective component
Unit in defrost cycle
Wait for completion of cycle
Coil does not get cold enough to
reset thermostat.
Adjust fan delay setting of
thermostat.
Ice accumulating
in drain panel
Defective heater
Replace heater
Drain line plugged
Clean drain line
Defective drain line heater
Replace heater
Defective
timer
or
defrost
thermostat
Replace defective component.
