Honeywell T874 Product Data page 215

THERMOSTAT
1
FALL
H1
ANTICIPATOR
H1
2
H2
ANTICIPATOR
3
FALL
4
H3
5
H3
ANTICIPATOR
FALL
6
H2
8
RISE
C1
9
C1
ANTICIPATOR
10
C2
ANTICIPATOR
RISE
C2
11
RESET
12
Fig. 233. Schematic and hookup of T874W with Q674L. Used in heat pump applications.
THERMOSTAT
H1
ANTICIPATOR
FALL
H1
H2
ANTICIPATOR
FALL
H2
RISE
CO
C1
ANTICIPATOR
RISE
C1
1 POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OVERLOAD PROTECTION AS REQUIRED.
Fig. 234. Schematic and hookup of T874G with Q674B. Used in heat pump applications.
T874 MULTISTAGE THERMOSTATS AND Q674 SUBBASES
SUBBASE
AUTO
ON
FAN
SWITCH
SYSTEM
SWITCH
EM. HT.
HEAT
OFF
COOL
SUBBASE
1
FAN
SWITCH
2
AUTO
4
ON
6
SYSTEM
8 SWITCH
HEAT
9
AUX. HEAT
OFF
LED (RED)
10
COOL
215
SYSTEM COMPONENTS
COMPRESSOR
HIGH SPEED
Y1
AUX. HT.
W2
FAN
G
R
EM. HT.
E
B
EM. HT.
LED (YELLOW)
EM. HT. LIGHT
X
SERVICE
LED (RED)
SERVICE LIGHT
L
COOL
CHANGEOVER
O
COMPRESSOR
LOW SPEED
Y
OUTDOOR
RESET
T
SYSTEM COMPONENTS
COMPRESSOR
CONTACTOR
Y1
FAN RELAY
G
L2
R
L1
(HOT)
1
W1
AUX. HT. RELAY
C
COOL
CHANGEOVER
VALVE
O
M3961
W89
HEAT
PUMP
CONTROL
PANEL
M3952
60-2485—8