Honeywell T874 Product Data page 174

T874 MULTISTAGE THERMOSTATS AND Q674 SUBBASES
THERMOSTAT
H1 ANTICIPATOR
FALL
H1
H2
ANTICIPATOR
H2
FALL
FALL
CHANGEOVER
C1
ANTICIPATOR
C1
1
POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OVERLOAD PROTECTION AS REQUIRED.
RISE
Fig. 167. Schematic and hookup of T874G with Q674F. Used in heat pump applications.
60-2485—8
SUBBASE
2
FAN SWITCH
3
AUTO
4
ON
5
SYSTEM
SWITCH
OFF
7
EM. HT.
HEAT
AUTO
8
COOL
9
10
R
W2
AUX. HT.
LED (GREEN)
X
EM. HT.
COMPRESSOR
LED (RED)
FAILURE
L
G
B
E
LACO
Y
174
SYSTEM COMPONENTS
(HOT) L1
ODT 1
RTD 1 EHR 1
RTD 2
ODT 2
EHR 2 RTD 3
RTD 1
RD
FAN RELAY
HEAT
CHANGEOVER
EM. HT.
VALVE
RELAY
EHT1
CHP
COMPRESSOR
CONTACTOR
L2
1
M1592A