T874 MULTISTAGE THERMOSTATS AND Q674 SUBBASES
111 60-24858
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
1POWER 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
1POWER 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