Wallmaster Service Manual (2010)

34
COOLING ONLY ROOM AIR CONDITIONERS: TROUBLESHOOTING TIPS
esuaC elbissoP melborP
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
temperature. 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
Broken, loose or incorrect wiring
Refer to appropriate wiring diagrams to check
wiring. Correct as needed.
esuaC elbissoP melborP
Fan motor
does not run
Inoperative system button
Broken, loose or incorrect wiring Refer to applicable wiring diagram. Repair.
Open capacitor Test capacitor & replace if inoperative
Fan speed button defective.
Inoperative fan motor
Test fan motor & replace if inoperative (be sure
internal overload has had time to reset)
esuaC elbissoP melborP
Does not cool or
only cools slightly
Undersized unit Refer to industry standard sizing chart
Indoor ambient thermistor open
or shorted.
See alarms. Replace thermistor if necessary.
Dirty fi launaM s’renwO ni dednemmocer sa naelC retl
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
Low capacity - undercharge Check for leak & make repair
Compressor not pumping properly
Check amperage draw against nameplate. If
not conclusive, make pressure test
Replace user interface if inoperative
Test button & replace user interface if inoperative
Possible Solution
Possible Solution
Possible Solution