Honeywell T874 - Schematic and Hookup of T874 N with Q674 F. Used in Heat Pump Applications

T874 MULTISTAGE THERMOSTATS AND Q674 SUBBASES
60-2485—8 182
Fig. 179. Schematic and hookup of T874N with Q674F. Used in heat pump applications.
L1
(HOT)
L2
1
W1
W2
EM. HT.
LED (RED)
CHECK
LED
(GREEN)
FAN RELAY
G
EM. HT.
RELAY
COMPRESSOR
CONTACTOR
Y
E
SYSTEM
SWITCH
EM. HT.
HEAT
OFF
COOL
H1
ANTICIPATOR
H1
H2
H2
ANTICIPATOR
1
POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OVERLOAD PROTECTION AS REQUIRED.
M3686
FALL
R
RISE
L
C1
HEAT
RELAY 3
EM.HT. RELAY
CONTACT
OUTDOOR
THERMOSTAT
AUTO
ON
FAN SWITCH
X
W3
OPTIONAL
COMPRESSOR
FAILURE DEVICE
DEFROST
RELAY
REVERSING
VALVE
EM.HT. RELAY
CONTACT
HIGH
PRESSURE
SWITCH
HEAT
RELAY 1
HEAT
RELAY 2
AUTO
FALL
CO
C1
ANTICIPATOR
1
2
4
5
6
8
9
10
THERMOSTAT
SUBBASE
SYSTEM COMPONENTS