WIRING
TYPICAL SYSTEM WIRING TABLE
50A66 | TERMINAL | SYSTEM COMPONENT | ||||
TERMINAL |
| TYPE |
| CONNECTION | ||
W |
|
|
|
| low voltage thermostat W terminal (or equivalent) | |
G | Terminal |
| low voltage thermostat G terminal (or equivalent) | |||
R | block with |
| low voltage thermostat R terminal (or equivalent) | |||
Y | captive |
| low voltage thermostat Y terminal (or equivalent) | |||
| screws |
|
| (2nd wire from Y terminal goes to 24 VAC HOT side of | ||
|
|
|
|
| compressor contactor coil) | |
C |
|
|
|
| 24 VAC COMMON side of compressor contactor coil | |
HLO (Pin 1) |
|
|
|
| high limit OUTPUT | |
Not Used (Pin 2) |
|
|
|
|
| |
TH (Pin 3) |
|
|
|
| 24 VAC transformer (low voltage HIGH side) | |
Not Used (Pin 4) | HLO | PSO | HLI | PSI |
| |
RO1 (Pin 5) | rollout switch OUTPUT | |||||
|
|
|
| |||
TR (Pin 6) | MV | RO | GND | RO | 24 VAC transformer (low voltage COMMON side) | |
LO | OUT | OUT | ||||
| ||||||
|
|
| ||||
HLI (Pin 7) | TH | TR | COM | MV | high limit INPUT | |
|
|
| MV |
|
| |
GND (Pin 8) |
|
|
|
| MUST BE RELIABLY GROUNDED TO CHASSIS | |
MV COM (Pin 9) |
|
|
|
| gas valve COMMON | |
PSI (Pin 10) |
|
|
|
| pressure switch INPUT | |
RO2 (Pin 11) |
|
|
|
| rollout switch INPUT | |
MV (Pin 12) |
|
|
|
| gas valve | |
IND |
|
|
|
| inducer HOT side | |
IGN | IND | IGN | IND | IGN | ignitor HOT side | |
IND N | N | N |
| |||
|
| inducer NEUTRAL side | ||||
|
|
|
| |||
IGN N |
|
|
|
| ignitor NEUTRAL side | |
COOL | 1/4” spade terminal | circulator blower COOL SPEED terminal | ||||
HEAT | 1/4” spade terminal | circulator blower HEAT SPEED terminal | ||||
PARK (3 terminals) | 1/4” spade terminal | unused circulator blower terminals | ||||
LINE | 1/4” spade terminal | input voltage (120 VAC) HOT side | ||||
XFMR | 1/4” spade terminal | 24 VAC transformer line voltage HOT side | ||||
EAC (optional) | 1/4” spade terminal | electronic air cleaner HOT side | ||||
HUM (optional) | 1/4” spade terminal | humidifier HOT side | ||||
120 VOLT NEUTRAL | 1/4” spade terminal | Terminals for 120 Volt NEUTRAL for line, transformer, | ||||
(5 terminals) |
|
|
|
| circulator, electronic air cleaner and humidifier | |
FP (E33) | 3/16” spade terminal | flame sensor probe* | ||||
FAN | 1/4” spade terminal | Circulator blower fan speed terminal | ||||
24 V HUM (E2) | 1/4” receptacle |
| 24 VAC humidifier | |||
* maximum recommended flame probe wire length is 36 inches.
5
