Bryant T874 Thermostat User Manual


 
T874 MULTISTAGE THERMOSTATS AND Q674 SUBBASES
101 60-24858
Fig. 53. Schematic and hookup of T874D with Q674B. Used in standard applications.
Fig. 54. Schematic and hookup of T874W with Q674B. Used in standard applications.
H1
FALL
W1
W2
G
Y2
Y1
HEAT RELAY 2
HEAT RELAY 1
H1
ANTICIPATOR
C1 ANTICIPATOR
AUTO
ON
FAN SWITCH
1
POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OVERLOAD
PROTECTION AS REQUIRED.
M3202A
L1
(HOT)
L2
1
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
R
SYSTEM
SWITCH
HEAT
OFF
COOL
L1 (HOT)
L2
1
W1
T
W2
HEAT RELAY 3
FAN RELAY
W3
HEAT CHANGEOVER VALVE
COMPRESSOR CONTACTOR 2
B
Y2
Y1
SYSTEM
SWITCH
HEAT
OFF
COOL
H1 ANTICIPATOR
C1
H1
FALL
H3
1
POWER SUPPLY. PROVIDE DISCONNECT
MEANS AND OVERLOAD PROTECTION
AS REQUIRED.
M3674
AUTO
ON
FAN SWITCH
FALL
R
COMPRESSOR CONTACTOR 1
HEAT RELAY 2
HEAT RELAY 1
G
C815A THERMISTOR
H2 ANTICIPATOR
FALL
H3 ANTICIPATOR
H2
C2 ANTICIPATOR
C2
RISE
RISE
COOL CHANGEOVER VALVE
O
C1 ANTICIPATOR
RESET HEATER
THERMOSTAT
SUBBASE
SYSTEM COMPONENTS
1
2
3
4
5
6
8
10
11