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

T874 MULTISTAGE THERMOSTATS AND Q674 SUBBASES
60-2485—8 202
Fig. 215. Schematic and hookup of T874L with Q674B. Used in heat pump applications.
H1
FALL
Y
H1
R
L
COMPRESSOR
CONTACTOR
RELAY 1
N.O. 2
HIGH
ON
SYSTEM
SWITCH
H1 ANTICIPATOR
C1 ANTICIPATOR
COOL
OFF
FAN
SWITCH
1
POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OVERLOAD
PROTECTION AS REQUIRED.
M2993
THERMOSTAT
SUBBASE
SYSTEM COMPONENTS
COOL
CHANGEOVER
VALVE
4
1
8
9
10
H2
FALL
RISE
C1
L1
(HOT
)
L2
1
H2 ANTICIPATOR
CHECK
LED (RED)
C
2
3
5
LO
MED
COMPRESSOR
CONTACTOR
S1
RELAY
S1
RELAY N.C.
H2
AUX. HT. RELAY
R1 RELAY N.C. 1
R1 RELAY
K1 RELAY
G1
K2 RELAY
G2
R2
RELAY
N.O. 1
7
O
FIELD
REMOVABLE
JUMPER
HEAT
11
12