T8400C AND T8401C ELECTRONIC THERMOSTATS
Mounting Decorator Cover Plate and
Wallplate to Wall
Level only for appearance. The thermostat func-
tions normally even when not level.
NOTE: Only SUPER TRADELINE® models have the
Mount decorator cover plate (SUPER TRADELINE®
model only), wallplate, T8400C or T8401C, and the
screws provided (see Fig. 2) as follows:
1. Place the desired decorator cover plate and the
wallplate at the desired location on the wall.
2. Pull the thermostat wire through the entrance hole
on the decorator cover plate, then through the wall-
plate entrance hole.
3. Select the two mounting holes that best fit the
4. Fasten the decorator cover plate and the wallplate
to the wall using the anchors and screws provided.
5. After wiring the wallplate, plug the hole to prevent
drafts from affecting the thermostat; see Wiring
Use an 18-gauge maximum wire for wiring the
T8400C and T8401C Thermostats.
All wiring must comply with local electrical codes and
ordinances. Disconnect the power supply to prevent
electrical shock or equipment damage.
NOTE: To ensure proper mounting of thermostat,
restrict all wiring to the shaded area on the left
side of the terminals. See Fig. 3.
Fig. 1. Typical location of thermostat.
The shape of the terminals permits insertion of straight or
wraparound wiring connections; either method is
acceptable. See Fig. 4.
The T8400C Thermostat is powered through the heating/
cooling system controls and is adaptable to most 4-wire,
18 to 30 Vac heating-cooling systems.
The T8401C Thermostat is powered directly from the
system transformer and is adaptable to most 5-wire, 18
to 30 Vac heating-cooling systems. Refer to Fig. 5 and 6
for typical wiring hookups.
3-7/8 IN. x 3-7/8 IN. DECORATOR COVER PLATE (SELECT MODELS).
DRILL 3/16 INCH HOLES (IF DRYWALL) OR 7/32 (PLASTER OR WOOD)
WHEN USING WALL ANCHORS.
Fig. 2. Mounting decorator cover plate
and wallplate to wall.
5-3/4 IN. x 5-3/4 IN.