Honeywell T874 Product Data page 195

THERMOSTAT
CO
FALL
H1
H1 ANTICIPATOR
FALL
C1
RISE
C1 ANTICIPATOR
1 POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OVERLOAD PROTECTION AS REQUIRED.
Fig. 203. Schematic and hookup of T874L with Q674C. Used in heat pump applications.
THERMOSTAT
H1
FALL
H1 ANTICIPATOR
H2
H2
ANTICIPATOR
FALL
C1
RISE
C1 ANTICIPATOR
C2 ANTICIPATOR
C2
RISE
1 POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OVERLOAD PROTECTION AS REQUIRED.
2 LED IS NOT LABELED. JUMPER W2 TO X FOR AUXILIARY HEAT INDICATION. JUMPER E TO X FOR
EMERGENCY HEAT INDICATION. CONNECT SYSTEM MONITOR TO X TO IDENTIFY WHEN SYSTEM
NEEDS TO BE CHECKED.
Fig. 204. Schematic and hookup of T874D with Q674F. Used in standard applications.
SUBBASE
FAN SWITCH
2 AUTO
ON
3
4
6
SYSTEM
SWITCH
8
OFF
9
AUTO
10
SUBBASE
1
FAN
SWITCH
AUTO
ON
4
6
SYSTEM
8 SWITCH
OFF
EM. HT.
9
HEAT
AUTO
10
COOL
11
195
T874 MULTISTAGE THERMOSTATS AND Q674 SUBBASES
COMPRESSOR
CONTACTOR
Y
G
R
HEAT CHANGEOVER
VALVE
W
COMP.
W2
FAULT
(RED)
A
W1
W2
LED
(RED)
Y2
Y1
SYSTEM COMPONENTS
L1
(HOT)
L2
FAN RELAY
COMPRESSOR
FAULT
M2981
SYSTEM COMPONENTS
L1
(HOT)
HEAT RELAY 1
L2
HEAT RELAY 2
R
X
2
B
EM. HT. RELAY
E
FAN RELAY
G
COMPRESSOR
CONTACTOR 2
COMPRESSOR
CONTACTOR 1
M2982A
60-2485—8
1
1