68-0075-2 G.H. Rev. 1-03
www.honeywell.com/yourhome
Automation and Control Solutions
Honeywell International Inc.
Honeywell Limited-Honeywell Limitée
1985 Douglas Drive North
35 Dynamic Drive
Golden Valley, MN 55422
Scarborough, Ontario
M1V 4Z9
Printed in U.S.A. on recycled
paper containing at least 10%
post-consumer paper fibers.
T834C, T8034C HEATING/COOLING THERMOSTATS
CHECKOUT
CAUTION
Checkout Method Hazard.
Can damage thermostat heat anticipator.
Avoid checking thermostat operation by shorting
across system control terminals.
IMPORTANT
— To ensure accurate temperature control, do not
touch or breathe on bimetal of thermometer.
Heating
1.
Set system switch to Heat and Fan switch to Auto.
2.
Move temperature setting lever about 10°F (6°C) above
room temperature.
• Gas or oil -fired systems: Heating starts immediately.
Fan starts after short delay.
• Heat pump and some central electric heating
systems: Heating and fan start.
3.
Move temperature setting lever about 10°F (6°C) below
room temperature.
• Gas or oil-fired systems: Heating shuts off
immediately. Fan shuts off after a short delay.
• Heat pump and some electric heat systems: Heating
and fan shut off.
Cooling
CAUTION
Equipment Damage Hazard.
Can short-cycle air conditioner compressor.
Install minimum-off timer to provide five-minute time
delay to prevent operating compressor for five minutes
after thermostat turns off compressor or for five
minutes after system receives power.
Avoid operating thermostat in cooling applications
when outdoor temperature is below 50°F (6°C).
See air conditioner manufacturer recommendations.
1.
To prevent compressor short cycling, install a minimum
off-timer to provide a five-minute time delay. (The time
delay will not activate the compressor for five minutes
after the thermostat turns off the compressor or for five
minutes after the system receives power.)
2.
With System switch set to Cool and Fan switch set to
Auto, move the temperature setting lever about 10°F
(6°C) below room temperature. Cooling and fan should
start immediately.
3.
Move temperature setting lever about 10°F (6°C) above
room temperature. Cooling and fan should shut off.
Fan
1.
With System switch set to Off and Fan switch set to On,
the fan runs continuously.
2.
Move Fan switch to Auto. In gas-fired or oil-fired sys-
tems, fan operation is controlled by thermostat in cool-
ing and by plenum fan control in heating. In heat pump
and some central electric heat systems, fan operation is
controlled by the thermostat in both heating and cooling.
Recalibration
These thermostats are calibrated at the factory and should not
require recalibration. If thermostat seems out adjustment, first
check for accurate levelling. To check calibration:
1.
Move temperature setting lever to low end of tempera-
ture scale. (
System switch must be placed to Off.
Wait at least five minutes.)
2.
Remove thermostat cover. Move temperature setting
lever until switch just makes contact. (The mercury in
the switch will drop to the contact end of the tube.)
3.
Replace the thermostat cover and wait five minutes for
the cover and the thermostat to lose the heat it has
gained from your hands. (If the thermometer pointer and
the temperature lever indicator read approximately the
same, no recalibration is needed.)
4.
If recalibration appears necessary, use this procedure:
a. Place temperature setting lever at same setting as
thermometer.
b. Remove the thermostat cover.
c. Insert 104994A Calibration Wrench (ordered sepa-
rately) onto hex nut under coil. See Fig. 10. Holding
setting lever so it does not move, turn wrench clock-
wise until mercury rolls to right end of tube.
d. Remove wrench and replace thermostat cover.
e. Move temperature setting lever to low setting. Wait
at least five minutes for temperature to stabilize.
f. Slowly move the temperature setting lever until it
reads the same as the thermometer.
g. Remove cover. Holding temperature setting lever so
it does not move, reinsert the wrench and carefully
turn the wrench counterclockwise until the mercury
just rolls to the left end of the tube,
but no farther.
h. Recheck calibration by setting thermostat System
switch for the desired operation.
i.
Replace the cover.
Fig. 10. Recalibrating thermostat.
CALIBRATION
WRENCH
COIL SHOWN WITHOUT
HEAT ANTICIPATOR
M2044A