Refrigerant system diagnosis - cooling cycle – Friedrich KUHL R-410A User Manual
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Unit cools when
heat is called for
Incorrect wiring
Refer to applicable wiring diagram
Defective solenoid coil
Check for continuity of coil
Reversing valve fails to shift
Block condenser coil & switch unit to cooling.
Allow pressure to build up in system, then
switch to heating. If valve fails to shift, replace
valve.
Inoperative system switch
Check for continuity of system switch
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Cooling adequate,
but heating
insuffi cient
Heating capillary tube partially
restricted
Check for partially starved outer coil. Replace
heating capillary tube
Check valve leaking internally
Switch unit several times from heating to
cooling. Check temperature rise across
coil. Refer to specifi cation sheet for correct
temperature rise
Reversing valve failing to shift
completely; bypassing hot gas
Denergize solenoid coil, raise head pressure,
energize solenoid to break loose. If valve fails
to make complete shift, replace valve.
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)
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Moisture in System
Defective Compressor
Defective Compressor
REFRIGERANT SYSTEM DIAGNOSIS - COOLING CYCLE
HEAT PUMP ROOM AIR CONDITIONERS: TROUBLE SHOOTING TIPS
TROUBLESHOOTING CHART - HEAT PUMP