Bryant Q674 Thermostat User Manual


 
T874 MULTISTAGE THERMOSTATS AND Q674 SUBBASES
193 60-24858
Fig. 199. Schematic and hookup of T874G with Q674F. Used in heat pump applications.
Fig. 200. Schematic and hookup of T874R with Q674L. Used in heat pump applications.
H1
FALL
O
G
R
E
X
FAN RELAY
W3 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.
M2977
B
COMPRESSOR
CONTACTOR
AUX. HT. RELAY
4
5
8
9
10
H2
FALL
RISE
C1
L1
(HOT)
L2
1
H2
ANTICIPATOR
2
CHECK
LED
(RED)
Y
AUX. HT. LED
(GREEN)
COOL
HEAT
W3
W2
EM. HT. RELAY
COMPRESSOR
FAULT
L
HEAT CHANGEOVER
VALVE
COOL CHANGEOVER
RELAY
3
11
12
CO
RISE
EM. HT.
LED (RED)
THERMOSTAT
SUBBASE
SYSTEM COMPONENTS
T
G
R
Z
X
W1
FAN RELAY
EM. HT.
OFF
SYSTEM
SWITCH
AUTO
ON
FAN SWITCH
1
POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OVERLOAD PROTECTION AS REQUIRED.
M2978
COMPRESSOR
CONTACTOR
SERVICE
1
3
6
11
L1
(HOT)
L2
1
2
SERVICE
LED
(YELLOW)
Y
EM. HT.
LED (RED)
COOL
HEAT
W2
OUTDOOR
THERMOSTAT
SEQ 2
K
SEQ 1
HEAT CHANGEOVER
VALVE
H2 ANTICIPATOR
RISE
H2
H1
C1
FALL
4
5
C1 ANTICIPATOR
12
H1 ANTICIPATOR
THERMOSTAT
SUBBASE SYSTEM COMPONENTS
OUTDOOR
THERMOSTAT