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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