60
COOLING ONLY ROOM AIR CONDITIONERS: TROUBLESHOOTING TIPS
Possible Solution
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Unit does not run
Fuse blown or circuit tripped
Replace fuse, reset breaker. If repeats, check
fuse or breaker size. Check for shorts in unit
wiring & components
Power cord not plugged in
Plug it in
System button in “OFF” position
Set correctly
Inoperative system button or open
electronic control board
Test for continuity. Check alarms. Correct
as needed.
Loose or disconnected wiring
control board or other components
Check wiring & connections. Reconnect per
wiring diagram
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Evaporator coil
freezes up
Dirty fi
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Restricted airfl ow
Check for dirty or obstructed coil. Use
pressure wash or biodegradable cleaning
agent to clean
Inoperative thermistor Check alarms. Replace as necessary.
Short of refrigerant
De-ice coil & check for leak
Inoperative fan motor
Test fan motor & replace if inoperative
Partially restricted capillary tube
De-ice coil. Replace capillary tube.
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Compressor runs
continually & does
not cycle off
Excessive heat load
Unit undersized. Test cooling performance &
replace with larger unit if needed. See sizing chart.
Restriction in line
Check for partially iced coil & check
temperature split across coil
Refrigerant leak
Find leak and repair.
Compressor relay contacts stuck
Check operation of t-stat. Replace if contacts
remain closed.
Remote wall T-stat incorrectly wired Refer to appropriate wiring diagram
Thermistor shorted
Replace thermistor or electronic control board
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Electronic control
board does not
turn unit off
Compressor relay contacts stuck
Replace electronic control board
Temperature set at coldest point
Turn to higher temp. setting to see if unit
cycles off. If not, replace control board.
Incorrect wiring
Refer to appropriate wiring diagrams
Unit undersized for area to be
cooled
Refer to industry standard sizing chart
Defective thermistor
Replace thermistor or electronic control board
Possible Solution
Possible Solution
Possible Solution
