Bryant T874 Manual

A SERVICE OF

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T874 MULTISTAGE THERMOSTATS AND Q674 SUBBASES

5 60-2485—8

Models:

See Table 4.

Electrical Ratings:

Switch Contacts: 2.5A at 30 Vac

(

7.5A inrush

)

.

LED Li

g

hts

(

Optional

)

: 30 Vac.

Switches:

Two slide switches

(

one switch on Q674G and K;

no switches on Q674D

)

operated b

y

levers. Switch position

is shown on scaleplate.

Mounting:

Desi

g

ned to mount horizontall

y

on an outlet box

or the wall. Adapter plate assembl

y

available for mountin

g

on a vertical outlet box

(

see Subbase Accessor

y)

.

Finish:

Dark brown or

g

ra

y

.

Dimensions in in. (mm):

3-1/2

(

89

)

hei

g

ht; 5-5/8

(

143

)

width;

5/16

(

8

)

depth. See Fi

g

. 1.

Table 4. Q674 Subbase Specifications.

— Fast c

y

clin

g

. Electric Heat 0.12-

0.6A

0.12-

0.6A

T874G—Heat pump, cool

chan

g

eover, with fast c

y

clin

g

.

T872G Heat Pump or

Standard

21

1

b

0-1.0A

c

0.1-1.2A 0-1.0A —

— Fixed anticipator for H2. 0.1-1.5A

— Fast c

y

clin

g

. 0.12-

0.6A

T874H—Use with Q674C. T872H Heat Pump or

Standard

11

1

b

0-1.0A

c

— 0-1.0A —

T874J—Heat pump. None Heat Pump 2 1

2

d

0-1.0A

e

0-1.5A

c

0-1.0A

c

—

T874K—Heat pump. None Heat Pump 2 1

1

b

0.1-1.2A

0-1.5A

c

0-1.5A —

T874L—Heat pump. None Heat Pump 2 1 — 0.1-1.2A 0.1-1.2A 0-1.5A —

T874N—Heat pump, heat

chan

g

eover.

T872N Heat Pump 2 1

1

b

0.1-1.2A 0.1-1.2A 0-1.0A —

T874P—Heat pump. None Heat Pump 2 1 — 0.1-1.2A 0.1-1.2A 0-1.5A —

T874Q—Ni

g

ht setback heatin

g

. T872Q Standard

1

e

——0.1-1.2A ———

T874R—Heat pump. T872R

Heat Pump

f

21—

0-1.5A

c

0.1-1.2A 0-1.5A —

T874S—Two-speed compressor heat

pump.

None Heat Pump 2 2

1

g

0-1.2A

c

0-1.2A

c

0-1.2A 0-1.0A

T874V—Standard. None Standard — 1 —— —0-1.5A —

T874W—Heat pump and standard.

— Ni

g

ht setback heatin

g

.

T872W Heat Pump or

Standard

32—

0-1.2A

b

0-1.2A

c,d

0-1.2A 0-1.0A

a

Department of Defense.

b

Chan

g

eover sta

g

e operates with heatin

g

.

c

Fixed volta

g

e t

y

pe anticipation.

d

Chan

g

eover sta

g

e operates with heatin

g

; a secondar

y

chan

g

eover is provided in coolin

g

switch.

e

Provides ni

g

ht setback used with standard T874 and timer-operated remote switchin

g

.

f

Manual chan

g

eover sta

g

e—use Q674B,L subbase.

g

Chan

g

eover sta

g

e operates with coolin

g

.

Q674 Subbases

Models and Options Replaces Application

Switch Positions

Use WithSystem Fan

Q674A—Standard and TRADELINE®.

— Indicator LEDs.

Q672A Standard HEAT-AUTO-COOL AUTO-ON T874A-D

Q674B—Standard and TRADELINE. Q672B Standard HEAT-OFF-COOL AUTO-ON T874A-D

— Provision for fan rela

y

operation from Heat Pump T874G,H,L,R

external fan switch

(

isolate G terminal

)

. OVERRIDE-HEAT- AUTO-ON T874P

— Indicator LEDs. OFF-COOL

Q674C—Standard and TRADELINE. Q672C Standard OFF-AUTO AUTO-ON T874A-H,W

— Indicator LEDs. Heat Pump OVERRIDE-AUTO- AUTO-ON T874K,L,N

OFF T874P

Q674D—Standard and TRADELINE.

— For use when subbase switchin

g

is not

re

q

uired.

Q672D Standard None None T874A-F