Honeywell T834C Manual page 4

!
CAUTION
Do not check operation by shorting across termi-
nals of system controls. This will damage the heat
anticipator.
IMPORTANT: To assure accurate temperature control,
do not touch or breathe on bimetal or thermometer.
HEATING
With system switch set at HEAT and fan switch at
AUTO, move the temperature setting lever about 10° F
[6° C] above room temperature.
Gas or oil-fired systems—heating should start; fan should
start after a short delay.
Heat pump systems—both heating and fan should start.
Move temperature setting lever 10° F [6° C] below room
temperature.
Gas or oil-fired systems—heating should shut off and
fan should shut off after a short delay.
Heat pump systems—heating and fan should shut off.
COOLING
!
CAUTION
Do not operate cooling if outdoor temperature is
below 50° F [10° C]. Refer to manufacturer's
recommendations.
NOTE: To prevent compressor short cycling, a minimum
off-timer may be included to provide a five-minute time
delay before activating the compressor after the thermo-
stat last turned the compressor off, or after the system first
received power. This delay protects the compressor.
With the system switch set at COOL and fan switch at
AUTO, move the temperature setting lever about 10° F
[6° C] below room temperature. Cooling fan should start (see
NOTE above). Move the temperature setting lever about 10°
F [6° C] above room temperature. Cooling and fan should
shut off.
FAN
With the system switch set at OFF, and the fan switch at
ON, the fan should run continuously. Move the fan switch
to AUTO. In gas- or oil-fired systems, fan operation is
controlled by the thermostat in cooling and by the plenum
fan control in heating. In heat pump systems, fan operation
is controlled by the thermostat in both heating and cooling.
Home and Building Control
Honeywell Inc.
1985 Douglas Drive North
Golden Valley, Minnesota 55422
Checkout
Home and Building Control
Honeywell Limited—Honeywell Limitée
740 Ellesmere Road
Scarborough, Ontario
M1P 2V9
4
RECALIBRATION
These thermostats are calibrated at the factory and should
not need recalibration. If the thermostat appears to be out
of-adjustment, first check for accurate leveling.
To check calibration, proceed as follows:
1. Move the temperature setting lever to the low end of
the temperature scale. System switch must be placed at
OFF. Wait at least five minutes.
2. Remove the thermostat cover. Move the setting lever
until the switch just makes contact. The mercury in the
switch will roll to the left end of the tube.
3. Replace the 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 setting lever
indicator read approximately the same, no recalibration is
needed.
If recalibration appears necessary, proceed as follows:
1. Place the temperature setting lever at the same setting
as the thermometer. Remove cover.
2. Insert 104994A Calibration Wrench (order separately)
onto the hex nut under the coil. See Fig. 5. Holding the
setting lever so it does not move, turn the wrench
clockwise until the mercury rolls to the right end of
the tube. Remove wrench and replace cover.
3. Move the setting lever to a low setting. Wait at least
five minutes for temperature to stabilize.
4. Slowly move the setting lever until it reads the same
as the thermometer.
5. Remove cover. Holding the setting lever so it does
not move, reinsert wrench and carefully turn
counterclockwise until the mercury rolls to the left
end of the tube but no farther.
6. Recheck calibration. Set the thermostat system switch
for desired operation and replace the cover.
Fig. 5—Recalibration procedure.
COIL SHOWN WITHOUT
HEAT ANTICIPATOR
CALIBRATION
WRENCH
M2044
Helping You Control Your World
QUALITY IS KEY
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