Honeywell T874 - Schematic and Hookup of T874 C with Q674 C. Used in Heat Pump Applications; Schematic and Hookup of T874 A, C, D with Q674 E. Used in Standard Applications

T874 MULTISTAGE THERMOSTATS AND Q674 SUBBASES
115 60-2485—8
Fig. 81. Schematic and hookup of T874C with Q674C. Used in heat pump applications.
Fig. 82. Schematic and hookup of T874A,C,D with Q674E. Used in standard applications.
H1
FALL
L1
(HOT)
L2
1
H2 ANTICIPATOR
OFF
AUTO
FAN
SWITCH
CHANGEOVE
R
RELAY
M5981
POWER SUPPLY. PROVIDE DISCONECT MEANS
AND OVERLOAD PROTECTION AS REQUIRED.
1
SYSTEM COMPONENTSSUBBASETHERMOSTAT
1
4
6
8
9
10
W1
B
H2
FALL
C1
RISE
G
R
W2
Y1
C1 ANTICIPATOR
AUTO
ON
FAN
RELAY
COMPRESSOR
CONTACTOR
SYSTEM
SWITCH
H1
FALL
H2
FALL
C1
RISE
C2
RISE
L1
(HOT
)
L2
L1
(HOT
)
L2
1
1
1
2
3
POWER SUPPLY. PROVIDE DISCONNECT
MEANS AND OVERLOAD PROTECTION
AS REQUIRED.
JUMPER RC, RH FOR SINGLE TRANSFORMER.
O AND B TERMINALS ON SELECTED MODELS.
2
3
THERMOSTAT
SUBBASE
SYSTEM COMPONENTS
H1 ANTICIPATOR
H2 ANTICIPATOR
C2 ANTICIPATOR
C1
ANTICIPATOR
SYSTEM
SWITCH
FAN
SWITCH
AUTO
ON
OFF
HEAT
AUTO
COOL
HEAT RELAY 2
HEAT RELAY 1
COMPRESSOR
CONTACTOR 1
COMPRESSOR
CONTACTOR 2
FAN RELAY
1
4
6
8
9
10
11
RC
Y1
Y2
G
B
O
W2
W1
RH
M934