Friedrich WS10B10 service manual Cooling only Room AIR Conditioners Troubleshooting Tips

COOLING ONLY ROOM AIR CONDITIONERS: TROUBLESHOOTING TIPS

Problem	Possible Cause	Possible Solution
	Low voltage	Check voltage at compressor. 115V & 230V
		units will operate at 10% voltage variance
	Temperature not set cold enough or	Set temperature to lower than ambient
	room air thermistor inoperative	temperature. Test thermistor and replace
		if inoperative.
	Compressor hums but cuts off on	Hard start compressor. Direct test compressor.
Compressor	overload	If compressor starts, add starting components
does not run	Open or shorted compressor	Check for continuity & resistance
	windings
	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
	Broken, loose or incorrect wiring	Refer to appropriate wiring diagrams to check
		wiring. Correct as needed.

Problem	Possible Cause	Possible Solution
	Inoperative system button	Test button & replace user interface if inoperative
	Broken, loose or incorrect wiring	Refer to applicable wiring diagram. Repair.
Fan motor	Open capacitor	Test capacitor & replace if inoperative
does not run	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)

Problem	Possible Cause	Possible Solution
	Undersized unit	Refer to industry standard sizing chart
	Indoor ambient thermistor open	See alarms. Replace thermistor if necessary.
	or shorted.
Does not cool or	Dirty filter	Clean as recommended in Owner’s Manual
only cools slightly	Dirty or restricted condenser or	Use pressure wash or biodegradable cleaning
	evaporator coil	agent to clean
	Poor air circulation	Adjust discharge louvers. Use high fan speed
	Low capacity - undercharge	Check for leak & make repair
	Compressor not pumping properly	Check amperage draw against nameplate. If
		not conclusive, make pressure test

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