Honeywell T874 - Page 187

T874 MULTISTAGE THERMOSTATS AND Q674 SUBBASES
187 60-2485—8
Fig. 187. Schematic and hookup of T874C with Q674B. Used in standard applications.
Fig. 188. Schematic and hookup of T874D with Q674G. Used in standard applications.
L2
1
SYSTEM
SWITCH
OFF
H1
ANTICIPATOR
H1
FALL
1
POWER SUPPLY. PROVIDE DISCONNECT MEANS
AND OVERLOAD PROTECTION AS REQUIRED.
M395
6
C
C1
R3
H2
RISE
R1
C1
ANTICIPATOR
COOL
3
4
8
10
FALL
HEAT RELAY 1
R
R2
R5
HEAT RELAY 2
L1
(HOT)
X
5
HI SPEED
FAN RELAY
LO SPEED
FAN RELAY
HIGH
TEMP.
SWITCH
HIGH
PRESSURE
SWITCH
R4
HIGH
LOW
FAN
SWITCH
2
HEAT
H2
ANTICIPATOR
COOL
CONTACTOR
LOCKOUT
RELAY
LR
THERMOSTAT SUBBASE SYSTEM COMPONENTS
L1
(HOT
)
L2
1
SYSTEM
SWITCH
H1
ANTICIPATOR
H1
FALL
1
POWER SUPPLY. PROVIDE DISCONNECT MEANS
AND OVERLOAD PROTECTION AS REQUIRED.
M3958
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
T
H2
ANTICIPATOR
THERMOSTAT SUBBASE SYSTEM COMPONENTS
NO
FAN
SWITCH