Lennox 14HPX Unit Information page 6

Ambient and Coil Sensor
100
5750
90
7450
80
9275
70
11775
60 15425
19975
50
26200
40
30
20
10
0
10000 30000
RESISTANCE (OHMS)
FIGURE 5
Ambient Sensor The ambient sensor (shown in figure 6)
considers outdoor temperatures below −35°F (−37°C) or
above 120°F (48°C) as a fault. If the ambient sensor is de-
tected as being open, shorted or out of the temperature
range of the sensor, the control will not perform demand
defrost operation. The control will revert to time/tempera-
ture defrost operation and will display the appropriate fault
code. Heating and cooling operation will be allowed in this
fault condition.
NOTE − Within a single room thermostat demand, if
5−strikes occur, the board will lockout the unit. Defrost
board 24 volt power R" must be cycled OFF" or the
TEST" pins on board must be shorted between 1 to 2 sec-
onds to reset the board.
34375
46275
62700
85300
50000 70000 90000
AMBIENT
SENSOR
COIL SENSOR
Clip coil temperature sensor from the de-
frost board on the bend shown − 6th bend
up. Apply grease between bend and sen-
sor.
−
FIGURE 6
Defrost Temperature Termination Shunt (Jumper)
Pins The defrost control selections are: 50, 70, 90, and
100°F (10, 21, 32 and 38°C). The shunt termination pin is
factory set at 50°F (10°C). If the temperature shunt is not
installed, the default termination temperature is 90°F
(32°C).
Delay Mode
The defrost control has a field−selectable function to re-
duce occasional sounds that may occur while the unit is
cycling in and out of the defrost mode. When a jumper is
installed on the DELAY pins, the compressor will be cycled
off for 30 seconds going in and out of the defrost mode.
Units are shipped with jumper installed on DELAY pins.
Page 6