Honeywell T874 Product Data page 151

THERMOSTAT
1
H1
C1
FALL
2
H1/C1
ANTICIPATOR
3
4
H2
ANTICIPATOR
5
6
FALL
H2
8
10
1
POWER SUPPLY. PROVIDE DISCONNECT MEANS
AND OVERLOAD PROTECTION AS REQUIRED.
Fig. 134. Schematic and hookup of T874R with Q674L. Used in heat pump applications.
T874 MULTISTAGE THERMOSTATS AND Q674 SUBBASES
SUBBASE
FAN SWITCH
AUTO
ON
SYSTEM
SWITCH
EM. HT.
HEAT
OFF
COOL
151
SYSTEM COMPONENTS
RTD 1
G
R
W2
AUX. HT.
LED (GREEN)
E
COMP.
FAILURE
L
EM. HT.
LED (RED)
B
X
LACO
Y
CHANGEOVER VALVE (COOL)
O
ODT 1
EHR 1
RTD 2
ODT 2
EHR 2
RDT 3
FAN RELAY
L1
(HOT)
1
L2
EM. HT. RELAY
RTD 1
RD
CHANGEOVER
VALVE (HEAT)
COMPRESSOR
CONTACTOR
CHP
M106A
60-2485—8