T874 MULTISTAGE THERMOSTATS AND Q674 SUBBASES
161 60-24858
Fig. 150. Schematic and hookup of T874G with Q674F. Used in heat pump applications.
L1
HOT
L2
1
F
EM. HEAT
LED (RED)
V
SYSTEM
SWITCH
EM. HT.
HEAT
OFF
COOL
H1 ANTICIPATOR
1POWER SUPPLY. PROVIDE DISCONNECT MEANS
AND OVERLOAD PROTECTION AS REQUIRED. M2852A
R
H1
FALL
E
AUTO
ON
FAN SWITCH
VR
Y
M
OUTDOOR
THERMOSTAT SUPL. ELEC.
HT. RELAY
X
COOL CHANGEOVER VALVE
COMPRESSOR
CONTACTOR
OVERLOAD
SWITCH
INTERNAL
THERMOSTAT
HI PRESSURE
SWITCH
FAN
RELAY
EM. HT. RELAY
CONTACT TIME DELAY
FAN RELAY
TIME DELAY
FAN RELAY
SYSTEM
MONITOR
AUTO
H2
FALL
H2 ANTICIPATOR
CO
RISE
C1
RISE
C1
ANTICIPATOR
REMOVE FACTORY INSTALLED V-VR JUMPER WHEN CONNECTING
A TWO TRANSFORMER SYSTEM.
2
2
L1
HOT
L2 1
1
2
3
5
6
8
9
10
THERMOSTAT SUBBASE SYSTEM COMPONENTS