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T874 MULTISTAGE THERMOSTATS AND Q674 SUBBASES
223
60-2485—8
Fig. 248. Schematic and hookup of T874Y with Q674F. Used in heat pump applications.
M5923
L1
(HOT)
L2
1
C
E
R
FAN RELAY
COMPRESSOR
CONTACTOR 2
EM.HT. RELAY
MALFUNCTION
LED (RED)
LOW SPEED
LED (GREEN)
SYSTEM
SWITCH
HEAT
AUTO
COOL
C2
RISE
H1
FALL
2
3
4
8
H1
ANTICIPATOR
1
POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OVERLOAD PROTECTION AS REQUIRED.
THERMOSTAT
SUBBASE
SYSTEM COMPONENTS
Y2
Y1
OFF
COMPRESSOR
CONTACTOR 1
CO
RISE
9
10
11
C2
ANTICIPATOR
C1
ANTICIPATOR
L
G
HIGH SPEED
LED (YELLOW)
5
O
COOL
CHANGEOVER VALVE
AUX. HT. RELAY
W2
AUX. HT.
LED (RED)
7
RISE
C1
EM. HT.
FAN SWITCH
ON
AUTO
H2
FALL
H2 ANTICIPATOR