Honeywell T874 Product Data page 165

THERMOSTAT
H1 ANTICIPATOR
2
3
H1 FALL
4
H2
ANTICIPATOR
5
H2
FALL
6
8
9
RISE
C1
ANTICIPATOR
CHANGEOVER
10
RISE
C1
1 POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OVERLOAD
PROTECTION AS REQUIRED.
2 W3 TERMINAL ON SELECT MODELS.
Fig. 155. Schematic and hookup of T874G with Q674F. Used in heat pump applications.
T874 MULTISTAGE THERMOSTATS AND Q674 SUBBASES
SUBBASE
FAN
SWITCH
AUTO
ON
SYSTEM
SWITCH
OFF
COOL
AUTO
HEAT
EM. HT.
165
SYSTEM COMPONENTS
R
RTD1 OTD1
EHR1
2
W3
ODT2
W2
EHR2
AUX. HT.
LED (GRN)
RTD1
X
SYSTEM
MONITOR
EM. HT.
L
LED (RED)
G
RD
COOL
CHANGEOVER VALVE
O
E
COMPRESSOR
CONTACTOR
LACO
Y
L1
(HOT)
L2 1
RTD2
RTD3
FAN
RELAY
EM. HT.
RELAY
CHP
M1589
60-2485—8