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T874 MULTISTAGE THERMOSTATS AND Q674 SUBBASES
60-2485—8180
Fig. 175. Schematic and hookup of T874G with Q674J. Used in heat pump applications.
Fig. 176. Schematic and hookup of T874G with Q674C. Used in standard applications.
FALL
L1
(HOT)
L2
1
O
G
R
W2
E
L
C
Y
2
4
6
8
POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OVERLOAD
PROTECTION AS REQUIRED.
1
THERMOSTAT
SUBBASE
SYSTEM COMPONENTS
FAN
SWITCH
AUTO
ON
SYSTEM
SWITCH
SUPL. HT.
ON
OFF
M2112A
H1 ANTICIPATOR
D
COOL
CHANGEOVER VALVE
FAN RELAY
H.C.R. 1
H.C.R. 1
H.C.R.2
H.C.R. 2
H.C.R.3
COMPRESSOR
CONTACTOR
1
9
10
FALL
CO
RISE
C1 ANTICIPATOR
H2
ANTICIPATOR
C1
RISE
HEAT PUMP
(GRN)
DEFROST
(RED)
MANUAL
(RED)
AUTO
(YEL)
O.D.T.
H1
FALL
L1
(HOT)
L2
1
H1 ANTICIPATOR
2
OFF
AUTO
SYSTEM
SWITCH
FAN SWITCH
ON
AUTO
FAN RELAY
M5730
POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OVERLOAD PROTECTION AS REQUIRED.
SETBACK STAGE OFFSET 12°F (7°C) FROM H1 STAGE.
LEDS ON SOME MODELS.
1
SYSTEM COMPONENTSSUBBASETHERMOSTAT
SETBACK
FALL
CO
RISE
C1
RISE
3
4
6
8
10
9
Y2
G
R
L
2
2
Y1
COMPRESSOR
CONTACTOR
OPEN-NIGHT
CLOSED-DAY
C1 ANTICIPATOR
SETBACK RELAY
COOL
CHANGEOVER VALVE
LED
X1
C
X2
LED
3
3