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T874 MULTISTAGE THERMOSTATS AND Q674 SUBBASES
60-2485—896
WIRING DIAGRAMS
Fig. 44. Schematic and hookup of T874A,B,C,D,E,F with Q674B. Used in standard applications.
Fig. 45. Schematic and hookup of T874C,D with Q674B. Used in standard applications.
H1
FALL
L1
(HOT)
L2
1
RH
W1
W2
O
G
Y2
Y1
RC
HEAT RELAY 2
HEAT RELAY 1
HEAT
OFF
COOL
SYSTEM
SWITCH
H1 ANTICIPATOR
C1 ANTICIPATOR
AUTO
ON
FAN
SWITCH
2
1
POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OVERLOAD
PROTECTION AS REQUIRED.
JUMPER RH, RC FOR SINGLE TRANSFORMER.
2
M2903
B
HEAT CHANGEOVER
VALVE
L1
(HOT)
L2
1
COOL CHANGEOVER
VALVE
FAN RELAY
COMPRESSOR
CONTACTOR 2
COMPRESSOR
CONTACTOR 1
1
4
6
8
9
10
11
H2
FALL
C2 ANTICIPATOR
RISE
RISE
C1
C2
THERMOSTAT
SUBBASE SYSTEM COMPONENTS
H2 ANTICIPATOR
NOTE:
Model Heating Cool-
ing
No. Bulbs Bulbs
T874A H1 C1
T874B H1 C1,C2
T874C H1,H2 C1
T874D H1,H2 C1,C2
T874E C1,C2
T874D H1,H2
H1
FALL
L1
(HOT)
L2
1
RH
W1
W2
O
G
Y2
Y1
RC
HEAT RELAY 2
HEAT RELAY 1
HEAT
OFF
COOL
SYSTEM
SWITCH
H1 ANTICIPATOR
C1 ANTICIPATOR
AUTO
ON
FAN
SWITCH
2
1
POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OVERLOAD
PROTECTION AS REQUIRED.
JUMPER RH, RC FOR SINGLE TRANSFORMER.
2
M933C
B
HEAT CHANGEOVER
VALVE
L1
(HOT)
L2
1
COOL CHANGEOVER
VALVE
FAN RELAY
COMPRESSOR
CONTACTOR 2
COMPRESSOR
CONTACTOR 1
1
4
6
8
9
10
11
H2
FALL
C2 ANTICIPATOR
RISE
RISE
C1
C2
X1
3
OPTIONAL LED ON SOME MODELS.
THERMOSTAT
SUBBASE SYSTEM COMPONENTS
3
H2 ANTICIPATOR