Bryant T874 Thermostat User Manual


 
T874 MULTISTAGE THERMOSTATS AND Q674 SUBBASES
199 60-24858
Fig. 211. Schematic and hookup of T874G with Q674F. Used in standard applications.
Fig. 212. Schematic and hookup of T874A with Q674E. Used in standard applications.
H1
FALL
G
R
L
X
W2
FAN RELAY
W1 RELAY
EM. HT.
OFF
AUTO
SYSTEM
SWITCH
H1 ANTICIPATOR
C1
ANTICIPATOR
AUTO
ON
FAN SWITCH
1
POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OVERLOAD PROTECTION AS REQUIRED.
M2989
THERMOSTAT
SUBBASE
SYSTEM COMPONENTS
W1
COMPRESSOR
FAULT
AUX. HT. RELAY
3
4
6
8
10
H2
FALL
RISE
C1
L1
(HOT)
L2
1
H2
ANTICIPATOR
2
EM. HT.
LED (RED)
Y1
AUX. HT.
LED
(GREEN)
COOL
HEAT
COMPRESSOR
CONTACTOR
H1
FALL
W1
W2
HEAT RELAY 1
H1 ANTICIPATOR
C1 ANTICIPATOR
1
POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OVERLOAD PROTECTION AS REQUIRED.
RC -RH REMOVABLE JUMPER WHEN SPECIFIED.
M2990
THERMOSTAT
SUBBASE SYSTEM COMPONENTS
COMPRESSOR
CONTACTOR 2
COMPRESSOR
CONTACTOR 1
1
6
8
9
10
11
H2
FALL
C2 ANTICIPATOR
RISE
RISE
C1
C2
Y1
Y2
HEAT RELAY 2
L1
(HOT)
L2
1
H2
ANTICIPATOR
L1
(HOT)
L2
1
RC
RH
2
4
2
G
FAN RELAY
HEAT
AUTO
COOL
SYSTEM
SWITCH
AUTO
ON
FAN
SWITCH
OFF