Honeywell T874 Product Data page 220

T874 MULTISTAGE THERMOSTATS AND Q674 SUBBASES
THERMOSTAT
FALL
H1 ANTICIPATOR
H1
H2
ANTICIPATOR
H2 FALL
RISE
C1
C1 ANTICIPATOR
RISE
CO
Fig. 243. Schematic and hookup of T874G with Q674F. Used in heat pump applications.
THERMOSTAT
H1
ANTICIPATOR
H1
FALL
H2
ANTICIPATOR
H2
FALL
C1
ANTICIPATOR
CO
RISE
C1
CO
RISE
1 POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OVERLOAD
PROTECTION AS REQUIRED.
Fig. 244. Schematic and hookup of T874J with Q674J. Used in heat pump applications.
60-2485—8
SUBBASE
1
FAN SWITCH
AUTO
2
ON
4
6
SYSTEM
SWITCH
OFF
EM. HT.
HEAT
AUTO
COOL
8
9
10
POWER SUPPLY. PROVIDE DISCONNECT MEANS AND
11 1
OVERLOAD PROTECTION AS REQUIRED.
12
2 TERMINAL LABELED C/X ON SOME MODELS.
SUBBASE
2
FAN SWITCH
3
AUTO
4
ON
5
6
8
SYSTEM
9
SWITCH
SUPL. HT.
10
ON
11
OFF
12
O
G
B
R
E
L
EM. HT.
LED (RED)
2
X
AUX. HEAT
LED (GREEN)
W2
Y
R
Y
G
W2
SUPL. HEAT
LED (RED)
L
C
E
X
P
O
220
SYSTEM COMPONENTS
COOL CHANGEOVER
VALVE
FAN RELAY
B RELAY
EM. HT. RELAY
AUX. HEAT RELAY
COMPRESSOR
CONTACTOR
SYSTEM COMPONENTS
FAN RELAY
COMPRESSOR
CONTACTOR
HEAT
CHANGEOVER
VALVE NO. 1
HEAT
HEAT
O.D.T.
CHANGEOVER
CHANGEOVER
VALVE NO. 2
VALVE NO. 1
HEAT HEAT
CHANGEOVER CHANGEOVER
VALVE NO. 2 VALVE NO. 3
X RELAY
P RELAY
COOL CHANGEOVER
VALVE
L1
(HOT)
L2
1
M7715
L1
(HOT)
L2
1
M7743