
Page 69
31-5000751 Rev. 0
Unit Sensor Operation, Checkout and Status /Error Codes
OPERATION:
6-Pin Sensor Harness (LIQ, AMB, COIL)
Liquid Sensor (R7 - No Sensor)
There is no sensor located on positions 5 and 6 of the connector. A 10K Ohm resistor installed between pins 5 and 6 on the
cable harness provides continuity for this circuit.
Ambient Temperature Sensor (RT13)
Ambient temperatures, as read by the ambient temperature sensor connected to pin 3 and pin 4, which are below -35°F
(-37°C) or above 120°F (48°C) trigger a fault condition. If the ambient sensor is open, shorted, or out of the temperature
range of the sensor, the control displays the appropriate alert code. Heating and cooling operation is allowed in this fault
condition
Coil Temperature Sensor (RT21)
The liquid temperature sensor located on the outlet of the outdoor TXV is connected to pins 5 and 6.
4-Pin Suction Temperature Sensor / Liquid Temperature Sensor Harness
Suction Line Sensor (RT41)
Suction line temperature is read by the suction line temperature sensor between Pins 1 and Pin 2 of the 4-pin sensor
harness. Nominal Resistance of the sensor is 10K ohms at 77F. The control will display are E182 error code if the sensor
reads open or shorted for 24 hours. Cooling operation is allowed with this fault.
Liquid Line Temperature Sensor (RT36)
Liquid line temperature is read by the liquid line temperature sensor between Pins 3 and Pin 4 of the 4-pin sensor harness.
Nominal Resistance of the sensor is 10K ohms at 77F. The control will display are E184 error code if the sensor reads open
or shorted for 24 hours. Cooling operation is allowed with this fault.
SENSOR
RESISTANCE VALUES
RANGE (OHMS)
TEMP RANGE ºF
(ºC)
PIN# / WIRE
SLEEVE COLOR
NONE
OUTDOOR
AMBIENT
COIL
4 AND 3
(BLACK )
6 AND 5
(BROWN)
2 AND 1
-40 (-40) TO
140 (60)
336,000 to 2,487 (see table
17 on page 77 for exact
temperature to ohm readings)
N/A
N/A
-40 (-40) TO
140 (60)
336,000 to 2,487 (see table
17 on page 77 for exact
temperature to ohm readings)
OUTDOOR
AMBIENT
LIQUID LINE
TEMPERATURE
SENSOR HARNESS
BLACK WIRES WITH
BLACK
SLEEVE
BLACK WIRES WITH
BR0WN
SLEEVE
10 K OHM RESISTOR
Figure 42.
Temperature Sensor Specification
CHECKOUT:
Sensors connect to the outdoor control through a field-replaceable harness assembly that plugs into the outdoor control.
Through the sensors, the control detects outdoor ambient, coil and liquid temperature fault conditions. As the detected
temperature changes, the resistance across the sensor changes. Check sensor operation by reading ohms across pins
shown in Figure 42.