WIRING
TYPICAL SYSTEM WIRING TABLE
50A55 | 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 | |
TWIN* |
| one wire twinning terminal | |
|
|
| |
MV (2 terminals) |
| gas valve (both gas solenoids are connected in parallel) | |
TR |
| 24 VAC transformer (low voltage COMMON side) | |
TH |
| 24 VAC transformer (low voltage HIGH side) | |
RO1 |
| rollout switch OUTPUT | |
RO2 | rollout switch INPUT | ||
FP | connector | flame sensor probe† | |
PS | & harness | pressure switch INPUT | |
PSO |
| pressure switch OUTPUT | |
HLI |
| high limit INPUT | |
HLO |
| high limit OUTPUT | |
GND |
| MUST BE RELIABLY GROUNDED TO CHASSIS | |
|
|
| |
IND | inducer HOT side | ||
connector | |||
IGN | ignitor HOT side | ||
& harness | |||
|
|
| |
COOL | spade terminal | circulator blower COOL SPEED terminal | |
|
|
| |
HEAT | spade terminal | circulator blower HEAT SPEED terminal | |
|
|
| |
PARK (2 terminals) | spade terminal | unused circulator blower terminals | |
|
|
| |
LINE | spade terminal | input voltage (120 VAC) HOT side | |
|
|
| |
XFMR | spade terminal | 24 VAC transformer line voltage HOT side | |
|
|
| |
EAC (optional) | spade terminal | electronic air cleaner HOT side | |
|
|
| |
HUM (optional) | spade terminal | humidifier HOT side | |
|
|
| |
CIR N | spade terminal | circulator blower NEUTRAL terminal | |
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| |
LINE N | spade terminal | input voltage (120 VAC) NEUTRAL side | |
|
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| |
XFMR N | spade terminal | 24 VAC transformer line voltage NEUTRAL side | |
|
|
| |
EAC N (optional) | spade terminal | electronic air cleaner NEUTRAL side | |
|
|
| |
HUM N (optional) | spade terminal | humidifier NEUTRAL side | |
|
|
| |
spade terminal | inducer NEUTRAL side | ||
|
|
| |
spade terminal | ignitor NEUTRAL side |
* The twinning feature is available only on models with six screw terminals; one of these terminals will be designated “TWIN”. All 50A55 controls used in twinning applications must have the “TWIN” terminal.
†Maximum recommended flame probe wire length is 36 inches.
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