Honeywell Q674L User Manual

69-0392—9

3

T874R THERMOSTATS AND Q674L SUBBASES

M925

VERTICAL 
OUTLET
BOX

ADAPTER
RING

SUBBASE

COVER 
PLATE

MOUNTING
SCREWS (2)

MOUNTING
SCREWS (2)

1

SUBBASE

MOUNTING
SCREWS (2)

HORIZONTAL
OUTLET
BOX

1

2

2

NOT INCLUDED WITH UNIT.

ACCESSORY PARTS AVAILABLE (193121A).

1

2

WIRES THROUGH
WALL OPENING

WALL 

WALL
ANCHORS
(2)

SUBBASE

MOUNTING
SCREWS (2)

M926

MOUNTING
HOLES

2. Run wires to the thermostat location.
3. Pull wires through the cover plate (if used) and sub-

base cable opening. See Fig. 3.

Use 18 gauge, color-coded thermostat cable for
proper wiring.

4. Secure the cover plate (if used) and subbase with

the screws provided. Do not fully tighten the
subbase screws.

5. Level the subbase by using a spirit level. Firmly

tighten subbase mounting screws. See Fig. 3. The
subbase mounting holes provide for minor out-of-
level adjustments.

An incorrectly leveled subbase causes the
temperature control to deviate from setpoint.

All wiring must comply with local electrical codes and
ordinances. Follow equipment manufacturer wiring
instructions when available. To wire subbase, proceed as
follows:

1. Connect the system wires to the subbase. See Fig.

5-12. A letter code for identification is located near
each terminal. The terminal barrier permits straight
or conventional wraparound wiring connection. See
Fig. 4.

2. Firmly tighten each terminal screw.
3. Fit wires as close as possible to the subbase. Push

excess wire back into the hole.

4. Plug the hole with nonflammable insulation to

prevent drafts from affecting the thermostat.

SPIRIT LEVEL

MOUNTING 
HOLES (2)

M927

TOP 
MOUNTING 
HOLES (2)

WIRING
TERMINAL

THERMOSTAT
CABLE OPENING

TO SPRING FINGER 
CONTACTS ON THE 
THERMOSTAT 
(UP TO 12)

POST (2) FOR
MOUNTING
THERMOSTAT 

FOR STRAIGHT
INSERTION–
STRIP 5/16 IN. (8 MM)

FOR WRAPAROUND–
STRIP 7/16 IN. (11 MM)

SUBBASE TERMINAL SCREW

M928

BARRIER