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T874 MULTISTAGE THERMOSTATS AND Q674 SUBBASES
213 60-2485—8
Fig. 229. Schematic and hookup of T874G with Q674F. Used in heat pump applications.
Fig. 230. Schematic and hookup of T874R with Q674L. Used in heat pump applications.
H1
FALL
H2
FALL
CO
RISE
C1
RISE
L1
(HOT)
L2
1
2
1
2
POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OVERLOAD PROTECTION AS REQUIRED.
REMOVABLE JUMPER (INSTALLED).
THERMOSTAT
SUBBASE
SYSTEM COMPONENTS
O.D.S.
H1 ANTICIPATOR
H2 ANTICIPATOR
C1 ANTICIPATOR
SYSTEM
SWITCH
FAN
SWITCH
AUTO
ON
EM. HT.
OFF
HEAT
AUTO
COOL
ELECTRIC
HT. RELAY
ELECTRIC
HT. RELAY
M3264
1
2
3
4
5
6
8
9
10
11
O
T
C
E
W1
L
G
Y1
R
EM. HT. RELAY
EM. HT.
EM. HT.
LED (YELLOW)
RESET
COMP. RELAY
O.L.
IN. STAT.
HI. PRO
FAN RELAY
SERVICE
C815A OUTDOOR
THERMISTOR
COOL CHANGEOVER
VALVE
AUX. HT.
LED
(GREEN)
SERVICE
LED (RED)
H2
FALL
H1
FALL
C
L1
(HOT)
L2
1
1
POWER SUPPLY. PROVIDE DISCONNECT MEANS AND
OVERLOAD PROTECTION AS REQUIRED.
THERMOSTAT
SUBBASE
SYSTEM COMPONENTS
M5068
H1
ANTICIPATOR
C ANTICIPATOR
H2
ANTICIPATOR
11
6
5
4
3
2
1
FAN
SWITCH
AUTO
ON
SYSTEM
SWITCH
EM .HT.
HEAT
OFF
COOL
AUX. HT.
LED
(GREEN)
EM. HT.
LED
(RED)
Y
B
X
E
W2
R
G
L
O
W3
W3 RELAY
COOL
CHANGEOVER VALVE
COMPRESSOR
MONITOR
FAN RELAY
AUX. HT. RELAY
EM. HT. RELAY
HEAT
CHANGEOVER VALVE
COMPRESSOR
RELAY
CHECK
LED (RED)