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T874 MULTISTAGE THERMOSTATS AND Q674 SUBBASES
60-2485—8178
Fig. 171. Schematic and hookup of T874J with Q674J. Used in heat pump applications.
Fig. 172. Schematic and hookup of T874H with Q674B. Used in heat pump applications.
H1
FALL
C1
RISE
CO
L1
(HOT)
L2
1
H1 ANTICIPATOR
OFF
EM. HT.
SYSTEM
SWITCH
FAN
SWITCH
AUTO
ON
AUTO
EM. HT. LED
(RED)
2
FAN RELAY
M5729
POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OVERLOAD PROTECTION AS REQUIRED.
1
SYSTEM COMPONENTS
SUBBASE
THERMOSTAT
H2
FALL
CO
RISE
3
4
5
6
8
9
10
11
12
EXTERNAL JUMPER SUPPLIED BY HONEYWELL.
2
R
Y
G
F
C
E
X
P
O
W
1
2
H2 ANTICIPATOR
C1 ANTICIPATOR
COMPRESSOR
CONTACTOR
O.D.T.
HCR1
HCR1
"X" RELAY
"P" RELAY
COOL CHANGEOVER
VALVE
HCR2
HCR2 HCR3
H1
FALL
CO
RISE
L1
(HOT)
L2
1
1
POWER SUPPLY. PROVIDE DISCONNECT MEANS AND
OVERLOAD PROTECTION AS REQUIRED.
THERMOSTAT
SUBBASE
SYSTEM COMPONENTS
H1 ANTICIPATOR
C1 ANTICIPATOR
SYSTEM
SWITCH
FAN
SWITCH
AUTO
ON
OFF
HEAT
COOL
COOL
CHANGEOVER
VALVE
COMPRESSOR
CONTACTOR
M1401
FAULT
LED
(RED)
CHECK
FILTER
LED (YELLOW)
FAN RELAY
12
11
10
9
8
4
3
2
G
R
O
2
C
3
Y
RISE
C1