Honeywell T874 - Schematic and Hookup of T874 J, R with Q674 L. Used in Heat Pump Applications

T874 MULTISTAGE THERMOSTATS AND Q674 SUBBASES
60-2485—8 126
Fig. 102. Schematic and hookup of T874J,R with Q674L. Used in heat pump applications.
H2
FALL
H1
FALL
C1
L1
(HOT)
L2
1
L1
(HOT)
L2
1
2
POWER SUPPLY. PROVIDE DISCONNECT
MEANS AND OVERLOAD PROTECTION
AS REQUIRED.
FIELD WIRE JUMPER TO ALLOW SINGLE
SYSTEM TRANSFORMER.
1
2
THERMOSTAT
SUBBASE
SYSTEM COMPONENTS
H1/C1
ANTICIPATOR
H2 ANTICIPATOR
SYSTEM
SWITCH
FAN
SWITCH
AUTO
ON
OFF
HEAT
EM. HT.
COOL
INTERNAL
THERMOSTAT
OVERLOAD
SWITCH
SUPPL. ELEC.
HT. RELAY
COOL CHANGEOVER
VALVE
COMPRESSOR
CONTACTOR
M4726
EM. HT.
LED (RED)
EM. HT. RELAY
TIME DELAY
FAN RELAY
OUTDOOR
THERMOSTAT
EM. HT.
RELAY CONTACT
FAN RELAY
HIGH
PRESSURE
SWITCH
R
VR
X
E
Y
V
F
M
1
2
3
4
5
6
7