4
TH
TR
MV
MV
GND
PS
PS
HL
C
R
G
W
Y
IGN
IND
GND
GND
HUM
EAC
XFMR
LINE
M1
M2
FAN
HEAT
COOL
HUM N
EAC N
XFMR N
LINE N
CIR N
IGNITOR
Y
W
G
R
THERMOSTAT
GAS
VALVE
ROLLOUT
(N. C.)
HIGH LIMIT
(N. C.)
PRESSURE SWITCH
(N. O.)
FLAME
SENSOR
PROBE
COMPRESSOR
CONTACTOR
ELECTRONIC
AIR CLEANER
HUMIDIFIER
INDUCER
CIRCULATOR
BLOWER
50A62
24 VAC
120 VAC
24 VAC CLASS II
TRANSFORMER
HOT
(LINE) NEUTRAL
(LINE)
TH TR
Low Voltage (24 VAC)
Line Voltage (120 VAC)
LEGEND
N. C. = Normally closed switch
N. O. = Normally open switch