Lennox XC20-036-230-01 Installation And Service Procedure page 68

OUTDOOR
AMBIENT
LIQUID LINE
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 tem­
perature changes, the resistance across the sensor changes. Check sensor operation by reading ohms across pins shown
in figure 49.
NOTE - When checking the ohms across a sensor, be aware that a sensor showing a resistance value that is not within the
range shown in figure 49, may be performing as designed. However, if a shorted or open circuit is detected, then the sensor
may be faulty and the sensor harness will need to be replaced.
OUTDOOR AMBIENT
TEMPERATURE
SENSOR
XC20
TEMP RANGE ºF
SENSOR
(ºC)
N/A
NONE
OUTDOOR
AMBIENT
-40 (-40) TO
140 (60)
LIQUID LINE
BLACK WIRES WITH
BLACK SLEEVE
BLACK WIRES WITH
YELL0W SLEEVE
Figure 49. Temperature Sensor Specifications
Figure 50. Temperature Sensor Locations
RESISTANCE VALUES
RANGE (OHMS)
314669 and 3779
336,000 to 2,487 (see
table 15 on page 69 for
exact temperature to
ohm readings).
10 K OHM RESISTOR
LIQUID LINE SENSOR
CRANKCASE HEATER
THERMOSTAT (S40) OPENS AT
70ºF, CLOSES AT 50ºF
68
PIN# / WIRE
SLEEVE COLOR
6 AND 5
4 AND 3
(BLACK)
2 AND 1
(YELLOW)
TEMPERATURE
SENSOR HARNESS