Bryant T874 Thermostat User Manual


 
T874 MULTISTAGE THERMOSTATS AND Q674 SUBBASES
185 60-24858
Fig. 183. Schematic and hookup of T874G with Q674J. Used in heat pump applications.
Fig. 184. Schematic and hookup of T874A,F with Q674G. Used in standard applications.
L1
(HOT)
L2
1
FAN RELAY
SYSTEM
SWITCH
OFF
EM. HT.
H1
ANTICIPATOR
H1
FALL
1
POWER SUPPLY. PROVIDE DISCONNECT MEANS
AND OVERLOAD PROTECTION AS REQUIRED.
M3950
AUTO
ON
FAN
SWITCH
R
G
CO
W
Y
X
H2
RISE
E
O
C1
ANTICIPATOR
C1
RISE
L1
EM. HT.
LED (RED)
ON
1
2
4
6
8
9
10
AUX. HT.
LED (GREEN)
COMPRESSOR
CONTACTOR
COMPRESSOR
FAILURE
FALL
COOL CHANGEOVER
VALVE
2BH
O. D. S.
1BH SH
1BH
H2
ANTICIPATOR
THERMOSTAT SUBBASE SYSTEM COMPONENTS
L1
(HOT)
L2
1
SYSTEM
SWITCH
OFF
H1
ANTICIPATOR
H1
FALL
1
POWER SUPPLY. PROVIDE DISCONNECT MEANS
AND OVERLOAD PROTECTION AS REQUIRED.
M3953
RH
C1
Y1
H2
RISE
W1
C1
ANTICIPATOR
C2
RISE
AUTO
1
4
6
8
9
10
COMPRESSOR
CONTACTOR 2
FALL
HEAT RELAY 1
RC
Y2
11
C2
ANTICIPATOR
W2
HEAT RELAY 2
COMPRESSOR
CONTACTOR 1
L1
(HOT)
L2
1
H2
ANTICIPATOR
THERMOSTAT SUBBASE SYSTEM COMPONENTS
NO
FAN
SWITCH