The T87F Universal Thermostat provides temperature
control for 24 to 30 Vac residential heating, cooling or
heating-cooling systems. For heating systems, the T87F
mounts on the wallplate provided. For cooling only, or
heating-cooling, use the 137421A Heating-Cooling Wall-
plate (included) with remote switching, or order the Q539
Subbase, which provides switching at the thermostat loca-
The spdt switch makes one set of contacts on a tem-
perature fall to operate the heating system. The other set of
contacts make on a temperature rise to operate the cooling
system when the T87F is used to control cooling.
Heat anticipation is adjustable, 0.1 to 1.2A.
This control contains mercury in a sealed tube. Do not
place control in the trash at the end of its useful life.
If this control is replacing a control that contains mercury
in a sealed tube, do not place your old control in the trash.
Contact your local waste management authority for
instructions regarding recycling and the proper disposal
of this control, or of an old control containing mercury in
a sealed tube.
Installation and Setting
WHEN INSTALLING THIS PRODUCT...
1. Read these instructions carefully. Failure to fol-
low them could damage the product or cause a hazardous
2. Check the ratings given in the instructions and on
the product to make sure the product is suitable for your
3. Installer must be a trained, experienced service
4. After installation is complete, check out product
operation as provided in these instructions.
1. Disconnect the power supply before begin-
ning installation to prevent electrical shock
or equipment damage.
2. Do not short across coil terminals on relay.
This may burn out the heat anticipation.
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NOTE: The T87F was carefully adjusted at the factory.
Handle the thermostat carefully; rough handling may
decrease its accuracy.
Select a location about 1.5 m [5 ft.] above the floor in an
area with good air circulation at average temperature.
Do not mount thermostat where it may be affected by—
— drafts or dead spots behind doors and in corners.
— hot or cold air from ducts.
— radiant heat from the sun or appliances.
— concealed pipes and chimneys.
— unheated (uncooled) areas behind the thermostat.
MOUNTING WALLPLATE OR SUBBASE (Fig. 2)
1. Use spirit level to accurately level the wallplate or
subbase as in Fig. 1. Inaccurate leveling may cause
thermostat control deviation.
2. When using the T87F with a Q539 Subbase, follow
the mounting and wiring instructions included with
1. Place the wallplate on the wall at the desired loca-
tion. Pull the thermostat cable through the entrance hole.
2. Fasten wallplate. Do not tighten the screws.
3. Level according to Fig. 1; then tighten screws.
4. After wiring wallplate, plug hole to prevent drafts
from affecting thermostat.
NOTE: To mount T87 Thermostat on an outlet box, order
129044A Adapter Ring Assembly.
Fig. 1—Leveling wallplate or subbase with