Friedrich 2007 service manual Troubleshooting Chart Cooling, Refrigerant System Diagnosis Heating

HEAT / COOL ROOM AIR CONDITIONERS: TROUBLESHOOTING TIPS

Problem	Possible Cause	Action
	Incorrect wiring	Refer to applicable wiring diagram
	Defective solenoid coil	Check for continuity of coil
Unit cools when		Block condenser coil & switch unit to cooling.
		Allow pressure to build up in system, then
heat is called for	Reversing valve fails to shift
		switch to heating. If valve fails to shift, replace
		valve.
	Inoperative system switch	Check for continuity of system switch

Problem	Possible Cause	Action
	Heating capillary tube partially restricted	Check for partially starved outer coil. Replace
		heating capillary tube
		Switch unit several times from heating to
Cooling adequate,	Check valve leaking internally	cooling. Check temperature rise across
		coil. Refer to specification sheet for correct
but heating
		temperature rise
insufficient
		De-energize solenoid coil, raise head
	Reversing valve failing to shift completely;	pressure, energize solenoid to break loose.
	bypassing hot gas	If valve fails to make complete shift, replace
		valve.

TROUBLESHOOTING CHART — COOLING

REFRIGERANT SYSTEM DIAGNOSIS – HEATING

Low Suction Pressure	High Suction Pressure	Low Head Pressure	High Head Pressure
Low Load Conditions	High Load Conditions	Low Load Conditions	High Load Conditions
Low Air Flow Across	High Air Flow Across	Refrigerant System	Low Air Flow Across
Indoor Coil	Indoor Coil	Restriction	Outdoor Coil
Refrigerant System	Reversing Valve not	Reversing Valve not	Overcharged
Restriction	Fully Seated	Fully Seated
Undercharged	Overcharged	Undercharged	Noncondensables (air)
		in System
Moisture in System	Defective Compressor	Defective Compressor

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