Friedrich KUHL R-410A User Manual
Page 60
59
COOLING ONLY ROOM AIR CONDITIONERS: TROUBLESHOOTING TIPS
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Compressor
does not run
Low voltage
Check voltage at compressor. 115V & 230V
units will operate at 10% voltage variance
Temperature not set cold enough or
room air thermistor inoperative
Set temperature to lower than ambient position.
Test thermistor and replace if inoperative.
Compressor hums but cuts off on
overload
Hard start compressor. Direct test compressor.
If compressor starts, add starting components
Open or shorted compressor
windings
Check for continuity & resistance
Open overload
Test overload protector & replace if inoperative
Open capacitor
Test capacitor & replace if inoperative
Inoperative system button
Test for continuity in all positions. Replace if
inoperative switch or electronic board.
Broken, loose or incorrect wiring
Refer to appropriate wiring diagrams to check
wiring. Correct as needed.
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Fan motor
does not run
Inoperative system button
Test button & replace user interface if inoperative
Broken, loose or incorrect wiring
Refer to applicable wiring diagram
Open capacitor
Test capacitor & replace if inoperative
Fan speed button defective Replace user interface if inoperative
Inoperative fan motor
Test fan motor & replace if inoperative (be sure
internal overload has had time to reset)
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Possible Solution
Possible Solution
Possible Solution
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Does not cool or
only cools slightly
Undersized unit
Refer to industry standard sizing chart
or shorted
Indoor ambient thermistor open
See alarms and replace thermistor if needed.
Dirty fi
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Dirty or restricted condenser or
evaporator coil
Use pressure wash or biodegradable cleaning
agent to clean
Poor air circulation
Adjust discharge louvers. Use high fan speed
Fresh air or exhaust air door open
Close doors. Instruct customer on use of this
feature
Low capacity - undercharge
Check for leak & make repair
Compressor not pumping properly
Check amperage draw against nameplate. If
not conclusive, make pressure test