5
50M56
TERMINAL
TERMINAL
TYPE
SYSTEM COMPONENT
CONNECTION
TYPICAL SYSTEM WIRING TABLE
†
Maximum recommended flame probe wire length is 36 inches.
low voltage thermostat W terminal (or equivalent)
low voltage thermostat G terminal (or equivalent)
low voltage thermostat R terminal (or equivalent)
low voltage thermostat Y terminal (or equivalent)
(2nd wire from Y terminal goes to 24 VAC HOT side of
compressor contactor coil)
24 VAC COMMON side of compressor contactor coil
high limit OUTPUT
gas valve first stage
24 VAC transformer (low voltage HIGH side)
pressure switch OUTPUT
rollout switch OUTPUT
24 VAC transformer (low voltage COMMON side)
high limit INPUT
MUST BE RELIABLY GROUNDED TO CHASSIS
gas valve COMMON
pressure switch INPUT
rollout switch INPUT
gas valve second stage
inducer HOT side
ignitor HOT side
inducer NEUTRAL side
ignitor NEUTRAL side
W
G
R
Y
C
HLO (Pin 1)
MV LO (Pin 2)
TH (Pin 3)
PSO (Pin 4)
RO OUT (Pin 5)
TR (Pin 6)
HLI (Pin 7)
GND (Pin 8)
MV COM (Pin 9)
PSI (Pin 10)
RO IN (Pin 11)
MV HI (Pin 12)
IND (Pin 1)
IGN (Pin 2)
IND-N (Pin 3)
IGN-N (Pin 4)
COOL
LO HEAT
HI HEAT
PARK (2 terminals)
LINE
XFMR
EAC (optional)
CIR N
LINE N
XFMR N
EAC N (optional)
FS
circulator blower COOL SPEED terminal
circulator blower LO HEAT SPEED terminal
circulator blower HI HEAT SPEED terminal
unused terminals
input voltage (120 VAC) HOT side
24 VAC transformer line voltage HOT side
electronic air cleaner HOT side
circulator blower NEUTRAL terminal
input voltage (120 VAC) NEUTRAL side
24 VAC transformer line voltage NEUTRAL side
electronic air cleaner NEUTRAL side
flame sensor probe
†
HLO
PSO
HLI
PSI
GND
TH
TR
MV
LO
RO
OUT
RO
IN
MV
COM
MV
HI
IND
IGN
IND
N
IGN
N
Terminal
block with
captive
screws
spade terminal
spade terminal
spade terminal
spade terminal
spade terminal
spade terminal
spade terminal
spade terminal
spade terminal
spade terminal
spade terminal
spade terminal
WIRING
