Honeywell T874 Product Data page 221

THERMOSTAT
2
H1/C1
ANTICIPATOR
3
H1
C1
FALL
4
6
H2
ANTICIPATOR
FALL
H2
1 POWER SUPPLY. PROVIDE DISCONNECT
MEANS AND OVERLOAD PROTECTION
AS REQUIRED.
2 TERMINAL LABELED C/X ON SOME MODELS.
Fig. 245. Schematic and hookup of T874R with Q674L. Used in heat pump applications.
THERMOSTAT
H1 ANTICIPATOR
FALL
H1
H2 ANTICIPATOR
H2
FALL
C1
RISE
1
POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OVERLOAD
PROTECTION AS REQUIRED.
Fig. 246. Schematic and hookup of T874C with Q674G. Used in standard applications.
SUBBASE
FAN SWITCH
AUTO
ON
SYSTEM
SWITCH
EM. HT.
HEAT
OFF
COOL
SUBBASE
1
NO FAN
SWITCH
4
6
SYSTEM
SWITCH
OFF
AUTO
8
9
10
11
221
T874 MULTISTAGE THERMOSTATS AND Q674 SUBBASES
O
COOL CHANGEOVER
VALVE
G
B
B RELAY
R
E
L
EM. HT.
LED (RED)
2
X
AUX. HT.
LED (GREEN)
AUX. HT. RELAY
W2
Y
W1
W2
RH
RC
Y1
Y2
SYSTEM COMPONENTS
FAN RELAY
L1
(HOT)
L2
1
EM. HT. RELAY
COMPRESSOR
M7718
CONTACTOR
SYSTEM COMPONENTS
HEAT RELAY 1
HEAT RELAY 2
L2
L1
(HOT)
1
L1
(HOT)
L2
1
COOL CHANGEOVER
VALVE
M7717
60-2485—8