Lennox ELITE 12GCS Series Unit Information page 22

C−12CHP−024/048
Cooling
1− Internal thermostat wiring energizes terminal "O" by
cooling mode selection, energizing reversing valve L1.
2− Cooling demand initiates at Y1 in the indoor thermo-
stat.
3− 24VAC from Y1 energizes compressor cpntactor K1.
(12CHP048 only, Y1 energizes time delay DL8, which
energizes compressor contactor K1 if 5−minute delay
has been satisfied).
4− K1−1 and K1−2 close energizing compressor B1 and
outdoor fan motor B4.
5− Compressor B1 and outdoor fan B4 begin immediate
operation.
6− Evaporator blower B3 begins operation after 5−second
delay.
7− When cool demand is satisfied, "Y1" in the indoor ther-
mostat de−energizes K1 contactor. K1−1 and K1−2 open
de−energizing compressor B1 and outdoor fan B4.
Evaporator blower B3 de−energizes after 90 seconds
off time delay.
8− Terminal "O" is de−energized when internal thermostat
is out of cool mode, de−energizing reversing valve L1.
First Stage Heat
9− Heating demand initiates at "Y1" in the thermostat.
10− 24VAC energizes
(12CHP048 only, Y1 energizes time delay DL8, which
energizes compressor contactor K1 if 5−minute delay
has been satisfied).
11− K1−1 and K1−2 close, energizing compressor B1 and
outdoor fan B4.
12− Evaporator blower B3 energizes after 5 seconds.
13− When heat demand is satified, Y1 in the indoor thermo-
stat de−energizes K1. K1−1 and K1−2 open and de−en-
ergizes compressor B1 and outdoor fan B4.
14− Evaporator blower B3 de−energizes after 90 seconds.
Defrost Mode
14− During heating operation when outdoor coil tempera-
ture drops below 32_F (0_C) defrost switch S6 closes.
15− Defrost control CMC1 begins timing. If defrost thermo-
stat S6 remains closed at the end of 30, 60 or 90 minute
period, defrost control energizes and defrost begins
16− During defrost CMC1 energizes the reversing valve L1
and de−energizes the outdoor fan B4.
17− Defrost continues 10 minutes or until defrost thermo-
stat switch S6 opens. When defrost thermostat switch
opens, defrost control CMC1 loses power and resets.
18− When CMC1 resets, reversing valve L1 is de−energized
while outdoor fan B4 is energized.
Page 22
compressor contactor K1.