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 Yterminal (or equivalent)
(2ndwirefromYterminalgoesto24VAC HOT side of
compressor contactor coil)
24VAC COMMON side of compressor contactor coil
high limit OUTPUT
gas valve first stage
24VAC transformer (low voltage HIGH side)
pressure switch OUTPUT
rollout switch OUTPUT
24VAC transformer (low voltage COMMON side)
high limit INPUT
MUSTBERELIABLYGROUNDEDTO 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(Pin1)
MVLO(Pin2)
TH (Pin 3)
PSO (Pin 4)
RO OUT (Pin 5)
TR (Pin 6)
HLI (Pin 7)
GND(Pin8)
MVCOM(Pin9)
PSI(Pin10)
ROIN(Pin11)
MVHI(Pin12)
IND(Pin1)
IGN(Pin2)
IND-N(Pin3)
IGN-N (Pin 4)
COOL
LO HEAT
HI HEAT
PARK(2terminals)
LINE
XFMR
EAC (optional)
HUM (optional)
CIR N
LINE N
XFMR N
EAC N (optional)
HUM N (optional)
FS
circulator blowerCOOLSPEEDterminal
circulator blower LO HEATSPEEDterminal
circulator blower HI HEATSPEEDterminal
unused terminals
input voltage(120VAC) HOT side
24VAC transformer line voltage HOT side
electronic air cleaner HOT side
humidifier HOT side
circulator blower NEUTRAL terminal
input voltage(120VAC) NEUTRAL side
24VAC transformer line voltage NEUTRAL side
electronic air cleaner NEUTRAL side
humidifier 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
spade terminal
spade terminal