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T874 MULTISTAGE THERMOSTATS AND Q674 SUBBASES
183 60-2485—8
Fig. 180. Schematic and hookup of T874A,D with Q674J. Used in heat pump applications.
H1
FALL
L1
(HOT)
L2
1
H1
FALL
C1
RISE
C2
RISE
M5957
POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OVERLOAD PROTECTION AS REQUIRED.
FILTER LED ON SOME MODELS.
C2 ANTICIPATOR
C1 ANTICIPATOR
SYSTEM
SWITCH
EM. HT.
AUTO
OFF
FILTER
LED
(YELLOW)
R-3
R-6
RANDOM START
R-8 (OPT.)
R-5
R-5
T2
(HEAT PUMP
OPERATION) R-10
(BIOLERLESS
OPERATION ) R-11
EM. HT. RELAY
ELEC. HT. RELAY
STG. 2
R-10
R-2
R-1
FAN RELAY
R-6
OVERLOADR-6
COMPRESSOR
CONTACTOR
R-8
R-10
R-11
R-11
CHANGEOVER VALVE
ELEC. HT.
RELAY STG. 1
FAN DELAY
RELAY
W1
Y1
G
R
W2
EM. HT.
LED
(RED)
E
X2
Y2
X1
1
4
6
8
9
10
11
H1
ANTICIPATOR
1
2
2
H2
ANTICIPATOR
SYSTEM COMPONENTS
SUBBASE
THERMOSTAT
FAN
SWITCH
AUTO
ON