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Honeywell Q674F User Manual

Page 6

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6

T874G,R MULTISTAGE HEAT PUMP THERMOSTATS AND Q674F,J,L SUBBASES

H2

FALL

H1

FALL

C1

L1
(HOT)

L2

1

1

2

2

POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OVERLOAD PROTECTION AS REQUIRED.

REMOVE JUMPER FOR INDEPENDENT CONTROL OF W1 AND E TERMINALS.

THERMOSTAT

SUBBASE

SYSTEM COMPONENTS

H1/C1
ANTICIPATOR

H2
ANTICIPATOR

RESET

SYSTEM
SWITCH

FAN
SWITCH

AUTO

ON

OFF

HEAT

EM. HT.

COOL

COMPRESSOR
CONTACTOR

FAN RELAY

M1858

2

3

4

5

6

11

12

Y

T

C

X

E

R

G

O

COOL CHANGEOVER
VALVE

3R

SEQ 1

SEQ 2

EM. HT. RELAY

4R

4R

5R

HPS

4R

4R

C815A
OUTDOOR
THERMISTOR

SYSTEM
LED
(GREEN)

EM. HT.
LED
(RED)

W1

AUX. HT.
LED
(YELLOW)

Fig. 6. Internal schematic and typical hookup for T874R/Q674L in heat pump system with outdoor reset. Includes

AUX. HT., EM. HT. and SYSTEM LEDs.

C1

H1

H1/C1
ANTICIPATOR

FALL

H2
ANTICIPATOR

L1
(HOT)

L2

1

1

POWER SUPPLY. PROVIDE
DISCONNECT MEANS AND
OVERLOAD PROTECTION
AS REQUIRED.

H2

FALL

FAN RELAY

EM. HT. RELAY

B RELAY

AUXILIARY
HEAT RELAY

CHANGEOVER
RELAY

COMPRESSOR
RELAY

W2

G

O

E

EM. HT. RELAY

L

R

2

3

4

6

X

Y

B

AUXILIARY
HEAT
(GREEN)

EMERGENCY
HEAT
(RED)

26.5 VAC
TRANSFORMER

COOL

OFF

AUTO

ON

HEAT

EM. HT.

M6565

Fig. 7. Internal schematic and typical hookup for T874R/Q674L in heat pump system. Includes EM. HT and AUX.

HT. LEDs.