T874 MULTISTAGE THERMOSTATS AND Q674 SUBBASES
60-24858130
Fig. 109. Schematic and hookup of T874R with Q674L. Used in heat pump applications.
H2
FALL
L1
(HOT)
L21
1POWER SUPPLY. PROVIDE DISCONNECT
MEANS AND OVERLOAD PROTECTION
AS REQUIRED.
THERMOSTAT SUBBASE SYSTEM COMPONENTS
H1
FALL
C1 H1/ C1
ANTICIPATOR
SYSTEM
SWITCH
FAN
SWITCH
AUTO
ON
OFF
HEAT
EM. HT.
COOL
AUX. HT. RELAY
FAN RELAY
AUX. HT.
LED (GREEN)
COOL
CHANGEOVER
VALVE
COMPRESSOR
FAILURE
EM. HT.
LED (RED)
OUTDOOR
THERMOSTAT
OUTDOOR
THERMISTOR
COMPRESSOR
CONTACTOR
Y
O
X2
T
R
F
B
W
G
1
2
3
4
5
6
RESET
HEATER
M5071