
T874 MULTISTAGE THERMOSTATS AND Q674 SUBBASES
60-2485—8
176
Fig. 169. Schematic and hookup of T874G with Q674F. Used in heat pump applications.
H1
FALL
RISE
CO
L1
(HOT)
L2
1
3
C1
RISE
1
2
2
3
POWER SUPPLY. PROVIDE DISCONNECT MEANS AND
OVERLOAD PROTECTION AS REQUIRED.
TERMINAL LABELED C/X ON SOME MODELS.
W3 TERMINAL ON SOME MODELS ONLY.
C1 ANTICIPATOR
H1 ANTICIPATOR
FAN SWITCH
AUTO
ON
SYSTEM
SWITCH
AUTO
HEAT
OFF
COOL
1
2
4
6
8
9
10
O
W2
X
E
L
B
W3
R
G
Y
AUX. HT. RELAY
FAN RELAY
EM. HT. RELAY
B RELAY
M5986A
THERMOSTAT
SUBBASE
SYSTEM COMPONENTS
11
12
COMPRESSOR
CONTACTOR
EM. HT.
EM. HT.
LED (RED)
AUX. HT.
LED (GREEN)
COOL CHANGEOVER
VALVE
H2
FALL
H2
ANTICIPATOR
AUX HT. RELAY