Honeywell T874G Installation Instructions Manual page 6

T874G,R MULTISTAGE HEAT PUMP THERMOSTATS AND Q674F,J,L 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. 6. Internal schematic and typical hookup for T874R/Q674L in heat pump system with outdoor reset. Includes
H1
H1/C1
C1
ANTICIPATOR
FALL
H2
ANTICIPATOR
H2
FALL
1 POWER SUPPLY. PROVIDE
DISCONNECT MEANS AND
OVERLOAD PROTECTION
AS REQUIRED.
M6565
Fig. 7. Internal schematic and typical hookup for T874R/Q674L in heat pump system. Includes EM. HT and AUX.
69-0268—11
SUBBASE
2
FAN
SWITCH
AUTO
ON
3
4
SYSTEM
SWITCH
5
EM. HT.
HEAT
6
OFF
COOL
11
12
AUX. HT., EM. HT. and SYSTEM LEDs.
2
3
AUTO
4
ON
6
EM. HT.
HEAT
OFF
COOL
O
G
R
W1
AUX. HT.
LED
2
(YELLOW)
E
EM. HT.
LED
(RED) X
C
SYSTEM
C815A
LED
OUTDOOR
(GREEN)
THERMISTOR
T
Y
EMERGENCY
HEAT
(RED)
AUXILIARY
HEAT
(GREEN)
HT. LEDs.
6
SYSTEM COMPONENTS
COOL CHANGEOVER
VALVE
FAN RELAY
3R
SEQ 2
4R
5R
HPS
COMPRESSOR
CONTACTOR
L1
(HOT)
26.5 VAC
TRANSFORMER
R
EM. HT. RELAY
L
X
AUXILIARY
HEAT RELAY
W2
FAN RELAY
G
CHANGEOVER
RELAY
O
EM. HT. RELAY
E
COMPRESSOR
RELAY
Y
B RELAY
B
L1
(HOT)
1
L2
SEQ 1
EM. HT. RELAY
4R
4R
4R
M1858
L2
1