Honeywell T874 Product Data page 141

THERMOSTAT
2
H1 ANTICIPATOR
3
H1
FALL
4
5
H2 ANTICIPATOR
6
H2
FALL
8
C1
ANTICIPATOR
10
C1
RISE
1 POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OVERLOAD
PROTECTION AS REQUIRED.
Fig. 121. Schematic and hookup of T874C with Q674L. Used in heat pump applications.
T874 MULTISTAGE THERMOSTATS AND Q674 SUBBASES
SUBBASE
FAN
SWITCH
AUTO
ON
AUX. HT.
LED (GRN)
SYSTEM
SWITCH
EM. HT.
HEAT
OFF
COOL
141
SYSTEM COMPONENTS
R
COMPRESSOR
FAILURE
EHR1
L
EM. HT.
RTD1
LED (RED)
X
W2
RD
G
COOL CHANGEOVER
VALVE
O
E
COMPRESSOR
CONTACTOR
LACO
Y
HEAT CHANGEOVER
VALVE
B
L1
(HOT)
L2 1
ODT1
RTD2
ODT2
EHR2
RTD3
RTD1
FAN RELAY
EM. HT.
RELAY
CHP
M7012
60-2485—8