69-0774B—1
2
T874D MULTISTAGE THERMOSTAT AND Q674A,D SUBBASES
4.
Level the subbase using a spirit level. See Fig. 3,
and firmly tighten subbase mounting screws. The
subbase mounting holes provide for minor out-of-
level adjustments.
IMPORTANT
An incorrectly leveled subbase will cause the
temperature control to deviate from setpoint. It is
not a calibration problem.
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
Fig. 1. Installation of Q674 Subbase on outlet box.
WIRES THROUGH
WALL OPENING
WALL
WALL
ANCHORS
(2)
SUBBASE
MOUNTING
SCREWS (2)
M926
MOUNTING
HOLES
Fig. 2. Installation of Q674 Subbase on wall.
Wiring the Subbase
All wiring must comply with local electrical codes and
ordinances. Follow equipment manufacturer’s wiring
instructions when available. To wire subbase, proceed as
follows:
1.
Connect the system wires to the subbase. See
Fig. 5 and 6. A letter code is located near each
terminal for identification. The terminal barrier
permits straight or conventional wraparound wiring
connection. See Fig. 4.
Fig. 3. Subbase components and leveling procedure.
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 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
Fig. 4. Barrier configuration.
Mount Thermostat
1.
Remove the thermostat cover by pulling the bottom
edge of the cover upward until it snaps free of the
mounting slots.
NOTE:
The cover is hinged at the top and must be
removed by pulling up at the bottom.
2.
Carefully remove and discard the polystyrene
packing insert that protects the mercury switches
during shipment.
3.
Turn over thermostat base and note the spring
fingers that engage the subbase contacts. Make
sure the spring fingers are not bent flat, preventing
proper electrical contact with the subbase.
4.
Note the two tabs on the top inside edge of the
thermostat base. The tabs fit into corresponding
slots on top of the subbase. Mount the thermostat
on the subbase.
5.
Align the two captive mounting screws in the
thermostat base with the posts on the subbase. See
Fig. 7. Tighten both screws. Do not overtighten
screws or damage to subbase posts can result.
