Friedrich R-410A service manual Troubleshooting, Problem, Possible Cause, Possible Solution

TROUBLESHOOTING

Problem	Possible Cause	Possible Solution
	Power disconnected.	Check power source.
	Branch circuit fuse blown or circuit	Replace fuse, reset breaker. If repeats, check fuse
		or breaker size. Check for shorts in unit wiring and
	breaker tripped.
Unit does not run		components.
	Loose or disconnected wiring at	Check wiring & connections. Connect per wiring
	switch.	diagram.
	Inoperative switch (On-Off).	Test for continuity, 3 and 2, 5 and 6. If bad,
		replace.

Problem	Possible Cause	Possible Solution
	Dirty filter.	Clean as recommended in Owner's Manual.
	Restricted airflow.	Check for dirty or obstructed coil clean as
		required.
Evaporator coil	Inoperative thermostat.	Test for shorted thermostat or stuck contacts.
	Short of refrigerant.	De-ice coil and check for leak.
freezes up
		De-ice coil. Check temperature differential
	Partially restricted capillary.	across coil. Touch-test coil return bends for same
		temperature. Test for low running current.
	Inoperative fan motor.	Test fan motor & replace if inoperative.

Problem	Possible Cause	Possible Solution
	Excessive heat load.	Test cooling performance of unit. Unit undersized.
	Restriction in line.	Check for partially iced coil. Check temperature
		split across coil.
Compressor runs
		Check for presence of oil on silver soldered
continually. Does
	Refrigerant leak.	connections. Check for partially iced coil. Check
not cycle off.
		split across coil. Check for low running amperage.
	Thermostat contacts stuck.	Check operation of thermostat. Replace if contacts
		remain closed.
	Incorrect thermostat setting.	Set to correct setting.

Problem	Possible Cause	Possible Solution
	Loss of charge in thermostat bulb.	Replace thermostat.
Thermostat	Thermostat contacts open.	Test for continuity at terminals 1 and 2. Replace if
		defective.
does not turn on
compressor	Incorrect wiring or loose wires.	Connect per wiring diagram. Tighten loose wires.
	System switch open.	Test for continuity at switch terminals 2 and 3.

Problem	Possible Cause	Possible Solution
	Thermostat set at coldest point	Adjust.
Thermostat		Disconnect power to the unit. Remove cover of
	Thermostat contacts stuck.	thermostat and check if contact is stuck, if so
does not turn off
		replace thermostat.
compressor
	Switch (On-Off) shorted.	Test switch for open contacts at terminals 2 and 3
		with switch in “Off” position.

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