T874 MULTISTAGE THERMOSTATS AND Q674 SUBBASES
60-2485—8116
Fig. 83. Schematic and hookup of T874G with Q674C. Used in standard applications.
Fig. 84. Schematic and hookup of T874G with Q674E. Used in heat pump applications.
H1
FAN
SWITCH
ON
AUTO
CHECK LED
(RED)
M5982
POWER SUPPLY. PROVIDE DISCONECT MEANS
AND OVERLOAD PROTECTION AS REQUIRED.
1
4
6
8
9
10
11
H2 ANTICIPATOR
FALL
H2
RISE
C1
C1 ANTICIPATOR
RISE
C2
FALL
H1 ANTICIPATOR
1
RH
SYSTEM COMPONENTSSUBBASE
THERMOSTAT
L1
(HOT)
L2
1
L1
(HOT)
L2
1
COMPRESSOR
CONTACTOR 1
C2 ANTICIPATOR
AUTO
COOL
HEAT
OFF
X1
RC
W2
G
Y1
W1
HEAT RELAY 1
FAN RELAY
HEAT RELAY 2
COMPRESSOR
CONTACTOR 2
Y2
H1
FALL
H2
FALL
CO
RISE
C1
RISE
L1
(HOT)
L2
1
1
POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OVERLOAD
PROTECTION AS REQUIRED.
THERMOSTAT
SUBBASE
SYSTEM COMPONENTS
H1 ANTICIPATOR
H2 ANTICIPATOR
C1 ANTICIPATOR
SYSTEM
SWITCH
1
2
4
6
8
9
10
Y
V
F
M
R
FAN
SWITCH
AUTO
ON
OFF
HEAT
AUTO
COOL
AUX. HT.
RELAY
DEFROST
RELAY
DEFROST
RELAY
FAN RELAY
HIGH PRESSURE
SWITCH
DEFROST
SWITCH
COOL
CHANGEOVER
VALVE
OUTDOOR
FAN RELAY
COMPRESSOR
CONTACTOR
DEFROST
RELAY
M4666