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3. Adjust the charge to maintain a clear sight glass.
4. Allow the compressor to operate for about 10
additional minutes and measure the hot gas discharge
temperature.
5. Using an additional electronic thermometer, measure
the ambient.
6. Adjust the charge until the hot gas temperature equals
105ºF + ambient (+ or – 5ºF). Remove charge to
increase the temperature.
NOTE: A final charge adjustment will be required once the
conditions are suitable to operate the unit in the cooling
mode (outdoor temperature of 60°F or higher).
NOTE: When adjusting the charge, allow the compressor
to operate for about 10 minutes before taking readings.
NOTE: Subsequent opening and replace of the cap will
require only 1/2 to 1 hex flat. See the table below for the
torque required for an effective seal on the valve bonnet (1/6
turn past finger tight).
TUBING SIZE
5/8
1 3/8
After closing the valve bonnet, perform a final refrigerant
leak test on the valves and sweat connections. Return the
room thermostat to the desired settings.
TORQUE
(ft-lbs)
14
16
TROUBLESHOOTING ANALYSIS TABLE
COMPLAINT
1. Excessive charge of refrigerant in the
system.
High Head Pressure
2. Inadequate supply of air across the
condensor coil.
3. Non-condensate gases in the system.
1. System low on refrigerant.
Low Head Pressure
2. Compressor valve broken.
1. Liquid line valve closed.
2. Restricted liquid line.
3. The bulb of the thermal expansion valve
has lost its charge.
4. System low on refrigerant.
5. Dirty filters.
Low Suction Pressure
6. Coil frosted up.
7. Flash gas in the liquid line.
8. Quantity of air through evaporator not
adequate.
1. Expansion valve stuck open.
2. Expansion valve bulb not in contact with
High Suction Pressure
suction line.
3. Suction and/or discharge valve leaking or
broken.
1. Disconnect switch open (if equipped).
2. Blown fuse or fuse at disconnect switch (if
equipped).
Compressor will not
3. Thermostat set too high.
4. Selector switch in "OFF" position.
start.
5. Contactor and/or relay coils burned out.
6. Loose or open electrical connection in
either the control or power circuit.
1. No voltage is present.
Solenoid does not energize
when voltage is present.
1. Undercharged.
Defrost Control Adjustments
This heat pump uses a Time/Temperature method for
defrost. A thermal sensor electrically set to "Normally
Open" is wired to the electronic defrost control located
in the control box. The thermal sensor attached to the
condenser coil determines the outdoor coil temperature.
Both coil temperature and compressor "run time" determine
defrosting of the outdoor coil. Adjustments to the defrost
timing selection can be changed from the 60 minute factory
setting to either 30 or 90 minutes by moving the jumper on
the defrost control. For the system to initiate a defrost, the
following statements must be true:
• The Defrost Sensor is closed, and
• The compressor "run time" is equal to the timing
selection on the defrost board.
During defrost the following actions occur:
1. The reversing valve is energized and the heat pump
operates in the cooling mode.
2. The airhandler auxiliary heat (if equipped) is activated.
3. The condenser fan motor is shut-off.
If the defrost cycle has not terminated after ten (10)
minutes the control will override the defrost sensor and
revert to a heating mode.
The defrost control has test pins which can be useful
when troubleshooting in the heating mode. These test
pins accelerate the compressor run time counter. The
suggested method for accessing this feature is:
1. Run unit in heat mode.
2. Check unit for proper charge.
NOTE: Bands of frost indicate low refrigerant charge.
3. Shut off power to unit.
PROBABLE CAUSE
1. Purge or pump-down excessive charge.
2. Make certain that coil is not fouled in any way, or
that air is not re-circulating.
3. Purge these gases from the system. Recharge
system, if necessary.
1. Charge systen until sight glass is clear of bubbles.
2. Replace compressor.
1. Open the liquid line.
2. Replace filter-dryer.
3. Detach the bulb fron the suction line and hold in
one hand. If no liquid refrigerant goes through the
valve, replace the valve.
4. Test the unit for leaks. Add refrigerant until sight
glass is free from bubbles, after repairing leak.
5. Clean or replace filter.
6. Defrost and clean coil. Clean or replace filters.
7. Excessive liquid line drop. Check liquid line size.
8. Increase the blower speed.
1. Correct valve action or replace the valve.
2. Fasten bulb securely to suction line.
3. Replace compressor.
1. Close the disconnect switch (if equipped).
2. Check the cause of failure and replace the fuse (if
equipped).
3. Adjust to lower temperature.
4. Turn selector switch knob to "Cool" position.
5. Replace contactor and/or relay.
6. Inspect and secure all electrical connections.
1. Replace the reversing valve.
8
Check the wiring
1. Check for leaks.
REMEDY
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