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T874 MULTISTAGE THERMOSTATS AND Q674 SUBBASES
111 60-2485—8
Fig. 73. Schematic and hookup of T874G with Q674C. Used in heat pump applications.
Fig. 74. Schematic and hookup of T874H with Q674C. Used in heat pump applications.
H1
FALL
G
Y1
R
FAN RELAY
REVERSING
VALVE RELAY
OFF
AUTO
SYSTEM
SWITCH
H ANTICIPATOR
C ANTICIPATOR
AUTO
ON
FAN SWITCH
1
POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OVERLOAD PROTECTION AS REQUIRED.
M7008
THERMOSTAT
SUBBASE
SYSTEM COMPONENTS
Y2
OPEN-NIGHT
CLOSED-DAY
3
4
6
8
10
SETBACK
FALL
RISE
CO
L1
(HOT
)
L2
1
2
L
COMPRESSOR
CONTACTOR
SETBACK
RELAY
9
RISE
C1
L1
(HOT)
L2
1
FAN RELAY
Y2
SYSTEM
SWITCH
OFF
AUTO
H1
ANTICIPATOR
CO
H1
FALL
1
POWER SUPPLY. PROVIDE DISCONNECT MEANS
AND OVERLOAD PROTECTION AS REQUIRED.
SERVICE LED ON SELECT MODELS.
M3680A
AUTO
ON
FAN SWITCH
R
COMPRESSOR
CONTACTOR
COOL CHANGEOVER
VALVE
G
C1
RISE
RISE
O
C1
ANTICIPATOR
B
Y1
THERMOSTAT
SUBBASE
SYSTEM COMPONENTS
2
3
4
8
9
10
SERVICE LED
(YELLOW)
X
C
2
2
COMPRESSOR
FAULT