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

 

12-pin

rollout switch INPUT

FP

 

connector

flame sensor probe*

PS

 

& harness

pressure switch INPUT

HLI

 

 

high limit INPUT

HLO

 

 

high limit OUTPUT

GND

 

 

MUST BE RELIABLY GROUNDED TO CHASSIS

(unused terminal)

 

 

 

 

 

 

 

IND

 

4-pin

inducer HOT side

IGN

 

ignitor HOT side

 

connector

IND N

 

inducer NEUTRAL side

 

& harness

 

 

 

IGN N

 

 

ignitor NEUTRAL side

 

 

 

 

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

 

 

 

 

LINE N

 

spade terminal

input voltage (120 VAC) NEUTRAL side

 

 

 

 

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

 

 

 

 

*The twinning feature is available only on models with six screw terminals; one of these terminals will be designated “TWIN”. All 50A55-843 controls used in twinning applications must have the

“TWIN” terminal.

Maximum recommended flame probe wire length is 36 inches.

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White Rodgers 50A55-843 installation instructions Connection, Typical System Wiring Table