J. H. • 2-93 • • ©Honeywell Inc. 1993 • Form Number 69-0760
M3375
T834H
Heating Thermostat
TRADELINE
Application
The T834H is a mercury switch thermostat that provides
low voltage control of heating systems with an adjustable
heat anticipator and AUTO-ON fan switching.
Fig. 1—T834H in typical heat application.
POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OVERLOAD
PROTECTION AS REQUIRED.
M3559
T834H
L1
(HOT)
L2
TEMP. FALL
H1
H1
ANTICIPATOR
R
G
W
FAN RELAY
HEAT RELAY
1
FAN
SWITCH
ON
AUTO
1
MOUNTING AND WIRING
Disconnect power supply before beginning installation
to prevent electrical shock or equipment damage.
Be sure wiring complies with local codes and ordinances.
Mount the T834H vertically on a wall or an outlet box.
1. In replacement applications, check the existing
thermostat wires for cracked or frayed insulation. Replace
any wires in poor condition. If the wires are plastered onto
the wall, make a hole next to the wires and loosen the wires
so they can be pushed back into the wall later.
2. In new installations, run wiring (if necessary) to the
thermostat location.
3. Connect the wires to the terminals on the back of the
thermostat. See Fig. 1 for internal schematic and typical
hookup diagram.
4. Remove thermostat cover by pulling outward on
bottom edge of cover until it snaps free of the thermostat
base. Carefully remove and discard the foam plastic ship-
ping insert, which protects the switch and bimetal assembly
during shipping.
5. Set the adjustable heat anticipator indicator to match
the current draw of the primary heating control (see Heat
Anticipator Setting).
6. Push excess wire back through the hole and plug any
opening with insulation to prevent drafts that can affect
thermostat performance.
7. Loosely fasten the thermostat to the wall or outlet
box with a screw through the top mounting hole. Do not
tighten.
8. Level the thermostat exactly using a spirit level or
plumb line. Tighten the mounting screws.
IMPORTANT: This thermostat was calibrated at the factory
mounted at true level. Any inaccuracy in leveling
during mounting will cause control point deviation.
9. Replace the thermostat cover.
M3375
Recycling Notice
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.
If you have questions, call Honeywell at 1-800-468-1502.
Installation
WHEN INSTALLING THIS PRODUCT…
1. Read these instructions carefully. Failure to fol-
low them could damage the product or cause a
hazardous condition.
2. Check the ratings given in the instructions and on
the product to make sure the product is suitable for your
application.
3. Installer must be a trained, experienced service
technician.
4. After installation is complete, check out product
operation as provided in these instructions.
CAUTION
Disconnect power supply before beginning instal-
lation to prevent electrical shock or equipment
damage.
LOCATION
Locate the thermostat about 5 ft [1.5 m] above the
floor in an area with good air circulation and average
temperature.
Do not mount thermostat where it may be affected by:
— drafts or dead spots behind doors or in corners.
— hot or cold air from ducts.
— radiant heat from the sun, fireplaces, or appliances.
— concealed pipes and chimneys.
— unheated (uncooled) areas behind the thermostat,
such as an outside wall.
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