Honeywell T874 Product Data page 176

T874 MULTISTAGE THERMOSTATS AND Q674 SUBBASES
THERMOSTAT
FALL
H1 ANTICIPATOR
H1
H2
ANTICIPATOR
H2 FALL
RISE
C1
C1 ANTICIPATOR
RISE
CO
Fig. 169. Schematic and hookup of T874G with Q674F. 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
1
11
OVERLOAD PROTECTION AS REQUIRED.
12
2 TERMINAL LABELED C/X ON SOME MODELS.
W3 TERMINAL ON SOME MODELS ONLY.
3
O
G
B
3
W3
R
E
L
EM. HT.
LED (RED)
X
AUX. HT.
LED (GREEN)
W2
Y
176
SYSTEM COMPONENTS
COOL CHANGEOVER
VALVE
FAN RELAY
B RELAY
AUX HT. RELAY
EM. HT. RELAY
2
AUX. HT. RELAY
COMPRESSOR
CONTACTOR
M5986A
L1
(HOT)
L2
1