Lennox CHA16 Service Manual page 39

Electric Heat
Transformer T2
4th Stage Heat
Time Delay DL18
75kW Only
3rd Stage Heat
75kW Only
2nd Stage Heat
Time Delay DL4
1st Stage Heat
Time Delay DL2
Primary Limit S15
(208/230V only)
Redundant Limit S63
(460 & 575V only)
Secondary Limit S20
(2 each element)
(10 total 75 kW)
(12 total 90 kW)
1st Stage Heat Demand
Pilot Relay K9
K9 K19
DL18 DL5 DL4
3rd Stage 2nd Stage
2nd Stage Heat Demand
Pilot Relay K19
K75
DL2
K18
K17
K16
K15
1st Stage
GND
Primary Limit S15
(460 & 575V only)
Patch Plate
(in lieu of limit
208/230V only)
Page 39
5th Stage Heat
Contactor K75
75kW Only
5th Stage Heat
Fuse F3
75kW Only
F3
4th Stage Heat
Fuse F3
75kW Only
F3
4th Stage Heat
Contactor K18
75kW Only
3rd Stage Heat
F3
Fuse F3
3rd Stage Heat
Contactor K17
2nd Stage Heat
F3
Fuse F3
2nd Stage Heat
Contactor K16
1st Stage Heat
F3
Fuse F3
1st Stage Heat
Contactor K15
L3 L2 L1
Electric Heat
Terminal Strip TB3