Filter
Top Products
T874 MULTISTAGE THERMOSTATS AND Q674 SUBBASES
125 60-2485—8
Fig. 100. Schematic and hookup of T874W with Q674C. Used in standard applications.
Fig. 101. Schematic and hookup of T874R with Q674L. Used in heat pump applications.
L2
1
ON
H1 ANTICIPATOR
H2 ANTICIPATOR
H1
1
POWER SUPPLY. PROVIDE DISCONNECT MEANS AND
OVERLOAD PROTECTION AS REQUIRED.
MOMENTARY POSITION. SPRING RETURN TO "ON" UPON SWITCH RELEASE.
H1 AND C1 ARE DPST SWITCHES.
M532
Y1
W1
C2
ANTICIPATOR
C2 ANTICIPATOR
AUTO
FALL
FALL
FALL
HEAT RELAY 1
HEAT RELAY 2
HEAT RELAY 3
COMPRESSOR RELAY
L1
(HOT)
R
FAN RELAY
O
AUTO
OFF
SERVICE
LED (RED)
A
G
2
2
3
4
5
5
3
3
4
MOMENTARY
CIRCUIT
T
T
EXTERNAL
TEMP.
READOUT
THERMOSTAT SUBBASE SYSTEM COMPONENTS
FAN
SWITCH
SYSTEM
SWITCH
H3
RISE
RISE
H2
THERMISTER
COMPRESSOR
CONTACTOR 2
W2
W3
Y2
1
2
4
5
6
7
8
9
10
C1
C2
11
12
H3 OFFSET 12°F FROM H2 FOR NIGHT SETBACK.
THERMISTOR INTERNAL TO THERMOSTAT.
L1
(HOT)
L2
1
COOL CHANGEOVER
VALVE
W
SYSTEM
SWITCH
OFF
HEAT
H1/C1
ANTICIPATOR
H1
FALL
1
POWER SUPPLY. PROVIDE
DISCONNECT MEANS AND
OVERLOAD PROTECTION
AS REQUIRED.
M3718A
AUTO
ON
FAN SWITCH
R
COMPRESSOR
CONTACTOR
G
C1
B
Y
EM. HT.
LED (RED)
AUX. HT. RELAY
X
EM. HT.
H2
ANTICIPATOR
H2
FALL
COOL
O
FAN RELAY
2
3
4
5
6
THERMOSTAT SUBBASE
SYSTEM COMPONENTS