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T874 MULTISTAGE THERMOSTATS AND Q674 SUBBASES
60-2485—8132
Fig. 111. Schematic and hookup of T874R with Q674L. Used in heat pump applications.
L1
(HOT)
L2
1
COOL
HEAT
FALL
H2
SYSTEM
SWITCH
1
POWER SUPPLY. PROVIDE DISCONNECT MEANS AND
OVERLOAD PROTECTION AS REQUIRED.
M2851
OFF
H1
C1
2
REMOVE FACTORY INSTALLED V-VR JUMPER WHEN
CONNECTING A TWO TRANSFORMER SYSTEM.
COMPRESSOR
CONTACTOR
OVERLOAD
SWITCH
INTERNAL
THERMOSTAT
HIGH
PRESSURE
SWITCH
2
V
VR
M
F
L
Y
E
X
A
R
FAN RELAY
SERVICE
OUTDOOR
THERMOSTAT
EM. HT.
RELAY
SUPPL. ELEC.
HT. RELAY
EM. HT.
RELAY
EM. HT.
RELAY
C815A
OUTDOOR
THERMISTOR
COOL CHANGEOVER
VALVE
EM. HT. LED
(YELLOW)
SERVICE
LED (RED)
EM. HT.
AUTO
ON
FAN
SWITCH
RESET
HEATER
H1/ C1
ANTICIPATOR
H2
ANTICIPATOR
FALL
THERMOSTAT
SUBBASE
SYSTEM COMPONENTS
1
2
3
4
5
6
7