T874 MULTISTAGE THERMOSTATS AND Q674 SUBBASES
119 60-24858
Fig. 89. Schematic and hookup of T874D with Q674E. Used in standard applications. Fig. 90. Schematic and hookup of T874D with Q674G. Used in standard applications.
Y1
W1
RC
1M7023
THERMOSTAT SUBBASE SYSTEM COMPONENTS
B
Y2
G
W2
RH
X
H1 ANTICIPATOR
H2 ANTICIPATOR
C1
RISE
H1 FALL
FALL
H2
C2 RISE C2 ANTICIPATOR
C1 ANTICIPATOR
POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OVERLOAD
PROTECTION AS REQUIRED.
O
A
1
6
9
10
11
4
8
AUTO
ON
FAN
SWITCH
SYSTEM
SWITCH
HEAT
OFF
COOL
HEAT CHANGEOVER
VALVE
HEAT
RELAY 1
COMPRESSOR
CONTACTOR 1
FAN RELAY
HEAT RELAY 2
L1
(HOT)
L2 1
L1
(HOT)
L2 1
COOL CHANGEOVER
VALVE
COMPRESSOR
CONTACTOR 2
AUTO
FILTER
LED (YEL)
SERVICE
LED (RED)
W1
A2
A1
OFF
AUTO
SYSTEM
SWITCH
1M7022
THERMOSTAT SUBBASE SYSTEM COMPONENTS
X2
L1
(HOT)
L21
B
X1
W2
T
RC
H1 ANTICIPATOR
H2 ANTICIPATOR
C1 RISE
H1 FALL
FALL
H2
C2 RISE C2 ANTICIPATOR
C1 ANTICIPATOR
POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OVERLOAD
PROTECTION AS REQUIRED.
NO FAN
SWITCH
RH
O
1
6
9
10
11
4
7
Y2
Y1
HEAT RELAY 1
HEAT RELAY 2
T RELAY
HEAT
CHANGEOVER
VALVE
COMPRESSOR
CONTACTOR 2
COMPRESSOR
CONTACTOR 1
L1
(HOT)
L21
5
8
12
FILTER LED (YEL)
SERVICE
LED (RED)
FILTER
LED (YEL)
SERVICE
LED (RED)
COOL
CHANGEOVER
VALVE