Bryant T874 Thermostat User Manual


 
T874 MULTISTAGE THERMOSTATS AND Q674 SUBBASES
191 60-24858
Fig. 195. Schematic and hookup of T874G with Q674F. Used in heat pump applications.
Fig. 196. Schematic and hookup of T874G with Q674J. Used in heat pump applications.
H1
FALL
O
G
R
E
L
X
W2
FAN RELAY
COOL
CHANGEOVER
VALVE
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.
M2974
B
EM. HT.
RELAY
COMPRESSOR
CONTACTOR
AUX. HT. RELAY
1
4
6
8
9
10
H2
FALL
RISE
RISE
CO
C1
"B" RELAY
L1
(HOT)
L2
1
H2
ANTICIPATOR
2
EM. HT. LED
(RED)
Y
AUX.
HT. LED
(GREEN)
COOL
HEAT
THERMOSTAT
SUBBASE SYSTEM COMPONENTS
COMPRESSOR
FAULT
H1
FALL
O
G
R
E
L
W2
FAN RELAY
COOL
CHANGEOVER
VALVE
OFF
ON
SYSTEM
SWITCH
H1 ANTICIPATOR
C1 ANTICIPATOR
AUTO
ON
FAN SWITCH
1
POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OVERLOAD
PROTECTION AS REQUIRED.
M2975
COMPRESSOR
CONTACTOR
O.D.T.
1
4
6
8
9
10
H2
FALL
RISE
RISE
CO
C1
L1
(HOT)
L2
1
H2
ANTICIPATOR
2
SUPL. HT.
LED
(RED)
Y
SUPL. HT.
H.C.R.1
H.C.R.1
H.C.R.2
H.C.R.2
H.C.R.3
C
THERMOSTAT
SUBBASE SYSTEM COMPONENTS