Honeywell T874 Product Data page 161

THERMOSTAT
H1 ANTICIPATOR
1
FALL
2
H1
3
FALL
5
H2
H2 ANTICIPATOR
6
RISE
8
C1
RISE
9
C1
CO
ANTICIPATOR
10
1 POWER SUPPLY. PROVIDE DISCONNECT MEANS
AND OVERLOAD PROTECTION AS REQUIRED.
Fig. 150. Schematic and hookup of T874G with Q674F. Used in heat pump applications.
T874 MULTISTAGE THERMOSTATS AND Q674 SUBBASES
SUBBASE
R
M
FAN SWITCH
AUTO
F
ON
Y
SYSTEM
SWITCH
E
OFF
EM. HT.
X
HEAT
COOL
AUTO
VR
V
2 REMOVE FACTORY INSTALLED V-VR JUMPER WHEN CONNECTING
A TWO TRANSFORMER SYSTEM.
161
SYSTEM COMPONENTS
COOL CHANGEOVER VALVE
INTERNAL
COMPRESSOR
THERMOSTAT
CONTACTOR
OVERLOAD
SWITCH
FAN
RELAY
OUTDOOR
THERMOSTAT
EM. HT. RELAY
CONTACT
EM. HEAT
LED (RED)
SYSTEM
MONITOR
2
HI PRESSURE
SWITCH
SUPL. ELEC.
HT. RELAY
TIME DELAY
FAN RELAY
TIME DELAY
FAN RELAY
1
L1
HOT
L2
L2
1
L1
HOT
M2852A
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