Bryant T874 Thermostat User Manual


 
T874 MULTISTAGE THERMOSTATS AND Q674 SUBBASES
207 60-24858
Fig. 222. Schematic and hookup of T874B with Q674E. Used in standard applications.
Fig. 223. Schematic and hookup of T874S with Q674F. Used in heat pump applications.
M5920
L1
(HOT)
L2
1
C
W
R
FAN RELAY
COMPRESSOR
CONTACTOR 2
HEAT RELAY
MALFUNCTION
LED (RED)
LOW
SPEED
LED
(GREEN)
FAN SWITCH
ON
AUTO
SYSTEM
SWITCH
HEAT
AUTO
COOL
C1
RISE
H1
FALL
2
3
4
8
H1 ANTICIPATOR
1
POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OVERLOAD PROTECTION AS REQUIRED.
SUBBASE
SYSTEM COMPONENTS
Y2
Y1
OFF
COMPRESSOR
CONTACTOR 1
C2
RISE
9
10
11
C2
ANTICIPATOR
C1
ANTICIPATOR
L
G
HIGH SPEED
LED (YELLOW)
SYSTEM
MONITOR
THERMOSTAT
M5923
L1
(HOT)
L2
1
C
E
R
FAN RELAY
COMPRESSOR
CONTACTOR 2
EM.HT. RELAY
MALFUNCTION
LED (RED)
LOW SPEED
LED (GREEN)
SYSTEM
SWITCH
HEAT
AUTO
COOL
C2
RISE
H1
FALL
2
3
4
8
H1
ANTICIPATOR
1
POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OVERLOAD PROTECTION AS REQUIRED.
THERMOSTAT SUBBASE
SYSTEM COMPONENTS
Y2
Y1
OFF
COMPRESSOR
CONTACTOR 1
CO
RISE
9
10
11
C2
ANTICIPATOR
C1
ANTICIPATOR
L
G
HIGH SPEED
LED (YELLOW)
5
O
COOL
CHANGEOVER VALVE
AUX. HT. RELAY
W2
AUX. HT.
LED (RED)
7
RISE
C1
EM. HT.
FAN SWITCH
ON
AUTO
H2
FALL
H2 ANTICIPATOR