Honeywell T874 Product Data page 206

T874 MULTISTAGE THERMOSTATS AND Q674 SUBBASES
THERMOSTAT
H1
FALL
H1
ANTICIPATOR
FALL
H3
H2
ANTICIPATOR
H2
FALL
RISE
C1
RISE
C2
POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OVERLOAD PROTECTION AS REQUIRED.
1
2
MOMENTARY POSITION. SPRING RETURN TO "ON" UPON SWITCH RELEASE.
Fig. 220. Schematic and hookup of T874W with Q674C. Used in standard applications.
THERMOSTAT
H1 ANTICIPATOR
H1
FALL
RISE
CO
C1 ANTICIPATOR
RISE
C1
1 POWER SUPPLY. PROVIDE DISCONNECT MEANS
AND OVERLOAD PROTECTION AS REQUIRED.
Fig. 221. Schematic and hookup of T874H with Q674C. Used in heat pump applications.
60-2485—8
SUBBASE
1
SYSTEM
SWITCH
OFF
2
AUTO
4
5
6
7
FAN
SWITCH
AUTO
8
ON
9
2
10
SUBBASE
2
FAN SWITCH
3
AUTO
ON
4
8
9 SYSTEM
SWITCH
OFF
10
AUTO
W1
W2
W3
Y2
SERVICE
LED (RED)
Y1
Y1
G
R
Y2
B
O
X
SERVICE
LED (YELLOW)
X1
C
FILTER LED (RED)
X2
206
SYSTEM COMPONENTS
CONTROL MODULE
HEAT RELAY #1
HEAT RELAY #2
HEAT RELAY #3
COMPRESSOR CONTACTOR #2
SYSTEM MONITOR
A
FAN RELAY
G
L2
1
L1
R
(HOT)
MOMENTARY
O
CIRCUIT
COMPRESSOR CONTACTOR #1
SYSTEM COMPONENTS
COOL CHANGEOVER
VALVE
1
FAN RELAY
COMPRESSOR
CONTACTOR
24 VAC
M5929
L2
L1
(HOT)
M5902