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 Lights (Optional): 30 Vac.
Switches:
Two slide switches (one switch on Q674G and K;
no switches on Q674D) operated by levers. Switch position
is shown on scaleplate.
Mounting:
Designed to mount horizontally on an outlet box
or the wall. Adapter plate assembly available for mounting
on a vertical outlet box (see Subbase Accessory).
Finish:
Dark brown or gray.
Dimensions in in. (mm):
3-1/2 (89)height; 5-5/8 (143) width;
5/16 (8) depth. See Fig. 1.
Table 4. Q674 Subbase Specifications.
— Fast cycling.
Electric Heat
0.12-
0.6A
0.12-
0.6A
T874G—Heat pump, cool
changeover, with fast cycling.
T872G
Heat Pump or
Standard
2
1
1
b
0-1.0A
c
0.1-1.2A 0-1.0A
—
— Fixed anticipator for H2.
0.1-1.5A
— Fast cycling.
0.12-
0.6A
T874H—Use with Q674C.
T872H
Heat Pump or
Standard
1
1
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
changeover.
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—Night setback heating.
T872Q
Standard
1
e
—
—
0.1-1.2A
—
—
—
T874R—Heat pump.
T872R
Heat Pump
f
2
1
—
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.
— Night setback heating.
T872W
Heat Pump or
Standard
3
2
—
0-1.2A
b
0-1.2A
c,d
0-1.2A
0-1.0A
a
Department of Defense.
b
Changeover stage operates with heating.
c
Fixed voltage type anticipation.
d
Changeover stage operates with heating; a secondary changeover is provided in cooling switch.
e
Provides night setback used with standard T874 and timer-operated remote switching.
f
Manual changeover stage—use Q674B,L subbase.
g
Changeover stage operates with cooling.
Q674 Subbases
Models and Options
Replaces
Application
Switch Positions
Use With
System
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 relay 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 switching is not
required.
Q672D
Standard None
None
T874A-F