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C4H5S, H4H5S, T4H5S: Installation Instructions
Major Components
Control Board
The Heat Pump control board controls the following functions:
• Compressor contactor operation
• Outdoor fan motor operation
• Reversing valve operation
• Defrost operation
• Compressor external protection
• Pressure switch monitoring
• Time delays
Field Connections
When using the Ion™ Communicating Control, 4 field wires are
required to be connected to the factory wires already wired to the
DX+DX-CR terminal
(Fig.
10). Unit as provided by manufacturer is set
up for the Ion™ Communicating Control.
When used with a standard non-communicating thermostat,5 field wires
are required to be connected to R, Y, W2, O and C. Disconnect factory
provided wires from DX+, DX-, C, and R terminals. Using factory
provided wires, connect to R, Y, W2, O and C terminals on the control
board. Connect field 24V wires to factory provided wires now connected
to R, Y, W2, O and C and unused factory provided wires.
When using Ion™ Communication Control only, the 24VAC LS (liquid
solenoid) output terminal is energized for the liquid solenoid accessory.
The connection is located at the side of the control board just below the
DX+DX-CR connector.
Compressor Internal Relief
The compressor is protected by an internal pressure relief (IPR) which
relieves discharge gas into the compressor shell when differential
between suction and discharge pressure exceeds 550-625 psi. The
compressor is also protected by an internal overload attached to motor
windings.
Troubleshooting
Systems Communicaiton Failure
If communication between Wall Control, and condensing unit is lost, the
outdoor control will flash the appropriate fault code
wiring to the Wall Control, indoor and outdoor units.
Pressure Switch Protection
The outdoor unit is equipped with high- and low-pressure switches. If
the control senses the opening of a high or low-pressure switch, it will
de-energize the compressor contactor, keep the outdoor fan operating for
15 minutes and display the appropriate fault code
After a 15 minute delay, if there is still a call for cooling, and the LPS or
HPS is reset, the compressor contactor is energized. If the LPS or HPS
has not closed after a 15 minute delay, the outdoor fan is turned off. If
the open switch closes anytime after the 15-minute delay, then the unit
will resume operation with a call for cooling.
If the LPS or HPS trips for five consecutive cycles, then unit operation is
locked out for 4 hours and the appropriate fault code (See table 3) is
displayed.
In the event of a high-pressure switch trip or high-pressure lockout,
check the refrigerant charge, outdoor fan operation and outdoor coil (in
cooling) for airflow restrictions, or indoor airflow in heating.
In the event of a low-pressure switch trip or low-pressure lockout, check
the refrigerant charge and indoor airflow (cooling) and outdoor fan
operation and outdoor coil in heating.
Control Fault
If the outdoor unit control board has failed, the control will flash the
appropriate fault code
(Table
3). The control board should be replaced.
Manufacturer reserves the right to change, at any time, specifications and designs without notice and without obligations.
24V Brown Out Protection
If the control voltage is less than 15.5 volts for at least 4 seconds, the
compressor contactor and fan relay are de-energized. Compressor and
fan operation are not allowed until control voltage is a minimum of 17.5
volts. The control will flash the appropriate fault code
the control voltage is in the allowable range of 18-30 volts.
Compressor Voltage Sensing
The input terminals labeled VR and VS on the control board (see
Fig.
of potential problems. The control continuously monitors the high
voltage on the run capacitor of the compressor motor. Voltage should be
present any time the compressor contactor is energized, and voltage
should not be present when the contactor is de-energized.
Compressor Thermal Cutout or Loss of 230V Power
If the control senses the compressor voltage after start-up, and is then
absent for 10 consecutive seconds while cooling demand exists, it will
de-energize the compressor contactor, keep the outdoor fan operating for
15 minutes (if 230V power present) and display the appropriate fault
code
loss of high voltage (230V) to compressor without loss of control
voltage.
After a 15 minute delay, if there is still a call for cooling, the compressor
contactor is energized. If the thermal protector has not re-set, the outdoor
fan is turned off. If the call for cooling continues, the control will
energize the compressor contactor every 15 minutes. If the thermal
protector closes, (at the next 15 minute interval check), the unit will
resume operation.
If the thermal cutout trips for three consecutive cycles, then unit
operation is locked out for 4 hours and the appropriate fault code
(Table
Contactor Shorted Detection
If there is compressor voltage sensed when there is no demand for
compressor operation, the contactor may be stuck closed. The control
will flash the appropriate fault code. Check the contactor and control box
wiring.
No 230V at Compressor
If the compressor voltage is not sensed when the compressor should be
starting, the contactor may be stuck open or the unit disconnect or circuit
breaker may be open. The control will flash the appropriate fault code.
(Table
3). Check the
Check the contactor, unit disconnect or circuit breaker and control box
wiring.
Temperature Thermistors
Thermistors are electronic devices which sense temperature. As the
temperature increases, the resistance decreases. Thermistors are used to
sense outdoor air (OAT) and coil temperature (OCT). Refer to
(Table
3).
for resistance values versus temperature.
If the outdoor air or coil thermistor should fail, the control will flash the
appropriate fault code
IMPORTANT: The outdoor air thermistor and coil thermistor are
factory mounted in the correct locations. Do not re-locate thermistor
sensors.
10
11) are used to detect compressor voltage status, and alert the user
(Table
3). Possible causes are compressor internal overload trip or
3) is displayed.
(Table
3).
THERMISTOR CURVE
90
80
70
60
50
40
30
20
10
0
0
20
40
(-17.77)
(-6.67)
(4.44)
TEMPERATURE °F (°C)
Fig. 12 – Resistance vs Temperature Chart
(Table
3). Verify
Fig. 12
60
80
100
120
(15.56)
(26.67)
(37.78)
(48.89)
A08054
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