Honeywell T874 - Page 186

T874 MULTISTAGE THERMOSTATS AND Q674 SUBBASES
60-2485—8 186
Fig. 185. Schematic and hookup of T874D with Q674E. Used in standard applications.
Fig. 186. Schematic and hookup of T874D with Q674G. Used in standard applications.
L1
(HOT)
L2
1
SYSTEM
SWITCH
AUTO
H1
ANTICIPATOR
H1
FALL
1
POWER SUPPLY. PROVIDE DISCONNECT MEANS
AND OVERLOAD PROTECTION AS REQUIRED.
M395
4
RH
C1
Y1
H2
RISE
W1
C1
ANTICIPATOR
C2
RISE
COOL
1
4
6
8
9
10
COMPRESSOR
CONTACTOR 2
FALL
HEAT RELAY
RC
Y2
11
C2
ANTICIPATOR
W2
HEAT RELAY 2
COMPRESSOR
CONTACTOR 1
L1
(HOT)
L2
1
AUTO
ON
FAN
SWITCH
FAN RELAY
IGNITION
RELAY
OFF
HEAT
B
G
H2
ANTICIPATOR
THERMOSTAT SUBBASE SYSTEM COMPONENTS
L1
(HOT
)
L2
1
SYSTEM
SWITCH
OFF
H1
ANTICIPATOR
H1
FALL
1
POWER SUPPLY. PROVIDE DISCONNECT MEANS
AND OVERLOAD PROTECTION AS REQUIRED.
M3955
RH
C1
Y1
H2
RISE
W1
C1
ANTICIPATOR
C2
RISE
AUTO
1
4
6
8
9
10
COMPRESSOR
CONTACTOR 2
FALL
HEAT RELAY 1
RC
Y2
11
C2
ANTICIPATOR
W2
HEAT RELAY 2
COMPRESSOR
CONTACTOR 1
L1
(HOT
)
L2
1
12
B
5
7
FAN RELAY
O
FAN RELAY
H2
ANTICIPATOR
THERMOSTAT SUBBASE SYSTEM COMPONENTS
NO
FAN
SWITCH