Friedrich KHM18A34A - Page 51

51 PB
HEAT PUMP ROOM AIR CONDITIONERS: TROUBLE SHOOTING TIPS
REFRIGERANT SYSTEM DIAGNOSIS - HEATING CYCLE
LOW SUCTION PRESSURE HIGH SUCTION PRESSURE LOW HEAD PRESSURE HIGH HEAD PRESSURE
Low Airflow Across
Outdoor Coil
Outdoor Ambient Too
High for Operation in
Heating
Refrigerant System
Restriction
Outdoor Ambient Too
High For Operation In
Heating
Refrigerant System
Restriction
Reversing Valve not
Fully Seated
Reversing Valve not
Fully Seated
Low Airflow Across
Indoor Coil
OverchargedUnderchargedOvercharged
Undercharged
Noncondensables (air)
in System
Noncondensables (air)
in System
Defective Compressor
Moisture in System
ELECTRICAL TROUBLESHOOTING CHART - HEAT PUMP
FAULT
SYSTEM COOLS WHEN
HEATING IS DESIRED
Is Selector Switch
Set For Heat?
Is Line Voltage
Present At The
Solenoid?
Is The Solenoid
Good?
YES
YES
Replace The
Solenoid
NO
Is The Reversing
Valve Stuck?
YES
Replace The
Reversing Valve
YES
TROUBLESHOOTING
Figure 718 (Trouble Shooting Tips)