GSZH5 Service Manual
72
SERVICING
WARNING
4. The measured voltage between circuit 3 and circuits
2 or 1 should be approximately 0VAC, which indicates
the relay contacts are closed. A voltage measurement
of approximately 115VAC indicates the relay is open.
Replace the control if the relay checks open when it
should be closed. See notes and cautions below.
fan motor disconnected will cause the high pressure
switch to trip.
The loss of charge protectors senses the pressure in the
liquid line and will open its contacts on a drop in pressure.
The low pressure control will automatically reset itself with
a rise in pressure.
The low pressure control is designed to cut-out (open) at
approximately 21 PSIG. It will automatically cut-in (close)
at approximately 50 PSIG. Test for continuity using a VOM
and if not as above, replace the control.
WARNING
The high pressure control capillary senses the pressure
in the compressor discharge line. If abnormally high
condensing pressures develop, the contacts of the control
open, breaking the control circuit before the compressor
motor overloads. This control is automatically reset.
Test 1. Testing High Pressure Control in Cooling Mode
1. Connect refrigerant gages to unit.
2. Disconnect power to outdoor unit.
3. Remove control panel cover.
4. Disconnect black wire from condenser fan motor
(single stage units) or remove plug from control board
on 2 stage units. NOTE: Tape or isolate black wire to
prevent possible short.
5. Apply power to unit and set thermostat to cool and set
for all for cool.
6. High pressure switch should open at 610 PSIG +/- 10
PSIG and close at 420 PSIG +/- 25 PSIG.
7. If high pressure switch does not operate in these
parameters replace switch.
1. Connect refrigerant gages to unit.
2. Disconnect power to indoor unit.
3. Remove control panel cover.
4. Disconnect black wire from evaporator fan motor
(single stage units) or remove plug from control board
on 2 stage units. NOTE: Tape or isolate black wire to
prevent possible short.
5. Apply power to unit and set thermostat to heat and set
for call for heat.
6. High pressure switch should open at 610 PSIG +/- 10
PSIG and close at 420 PSIG +/- 25 PSIG.
7. If high pressure switch does not operate in these
parameters replace switch.
With power ON:
WARNING
The low pressure control senses the pressure in the suction
line and will open its contacts on a drop in pressure. The
low pressure control will automatically reset itself with a rise
in pressure.
Test 1. Testing Low Pressure Control in Cooling Mode
1. Connect refrigerant gages to unit.
2. Disconnect power to indoor unit.
3. Remove control panel cover.
4. Disconnect black wire from evaporator fan motor
(single stage units) or remove plug from control board
on 2 stage units. NOTE: Tape or isolate black wire to
prevent possible short.