Honeywell T874 Product Data page 150

T874 MULTISTAGE THERMOSTATS AND Q674 SUBBASES
THERMOSTAT
FALL
H1
C1
H1/C1
ANTICIPATOR
H2
H2
FALL
ANTICIPATOR
RESET
POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OVERLOAD PROTECTION AS REQUIRED.
1
REMOVE JUMPER FOR INDEPENDENT CONTROL OF W1 AND E TERMINALS.
2
Fig. 132. Schematic and hookup of T874R with Q674L. Used in heat pump applications.
THERMOSTAT
H1/C1
ANTICIPATOR
H1
C1
FALL
H2 ANTICIPATOR
H2
FALL
1 POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OVERLOAD
PROTECTION AS REQUIRED.
Fig. 133. Schematic and hookup of T874R with Q674L. Used in heat pump applications.
60-2485—8
SUBBASE
2
FAN
SWITCH
AUTO
ON
3
4
SYSTEM
SWITCH
5
EM. HT.
HEAT
6
OFF
COOL
11
12
FAN
1
SWITCH
AUTO
2
ON
3
4
SYSTEM
SWITCH
5
EM. HT.
6
HEAT
OFF
COOL
O
COOL CHANGEOVER
VALVE
G
R
W1
AUX. HT.
LED
2
(YELLOW)
E
EM. HT.
LED
(RED) X
C
SYSTEM
C815A
LED
OUTDOOR
(GREEN)
THERMISTOR
T
Y
SUBBASE
EM. HT.
LED (YEL)
150
SYSTEM COMPONENTS
FAN RELAY
3R
SEQ 2
EM. HT. RELAY
4R
5R
HPS
COMPRESSOR
CONTACTOR
SYSTEM COMPONENTS
FAN
G
RELAY
R
K
AUX. HT.
RELAY
EM. HT.
RELAY
W2
L
COMPRESSOR
FAILURE
C
Z
RESET
LED (RED)
W1 RELAY
CO
W1
COMPRESSOR
CONTACTOR
Y
L1
(HOT)
1
L2
SEQ 1
4R
4R
4R
M1858
L1
(HOT)
L2 1
M2018