69-1598
6
T8034C HEATING/COOLING THERMOSTATS
Automation and Control Solutions
Honeywell Limited-Honeywell Limitée
35 Dynamic Drive Road
Scarborough, Ontario
M1V 4Z9
69-1598 G.H. 11-01
Automation and Control Solutions
Honeywell
1985 Douglas Drive North
Golden Valley, MN 55422
Printed in U.S.A. on recycled
paper containing at least 10%
post-consumer paper fibers.
CALIBRATION
WRENCH
COIL SHOWN WITHOUT
HEAT ANTICIPATOR
M2044A
CHECKOUT
CAUTION
Can cause damage to heat anticipator.
Do not check operation by shorting across
terminals of system controls.
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 the room temperature. In standard systems, the
heating should start and the fan should start after a short
delay. In heat pump or electric heat systems, both the
heating and fan should start.
Move the temperature setting lever about 10
°
F (6
°
C)
below the room temperature. In standard systems, the
heating should shut off and the fan should shut off after a
short delay. In heat pump or electric heat systems, both
the heating and fan should shut off.
COOLING
CAUTION
Can cause damage to compressor.
Do not operate cooling if outdoor temperature is
below 50
°
F (10
°
C). Refer to manufacturer recom-
mendations.
NOTE:
To prevent compressor short cycling, some
manufacturer equipment includes a minimum off-
timer to provide a five-minute time delay before
activating the compressor when the thermostat
last turned the compressor off, or from when 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 the room temperature. Cooling and fan should
start (see NOTE in COOLING section). Move the tempera-
ture setting lever about 10
°
F (6
°
C) above the 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 standard systems, fan operation is controlled
by the plenum fan control in heating and by the thermostat
in cooling. In heat pump or electric heat systems, fan
operation is controlled by the thermostat in heating and
cooling.
Recalibration
These thermostats are calibrated at the factory and should
not need recalibration. If the thermostat needs adjustment,
first check for accurate leveling.
To check calibration:
1.
Move the temperature setting lever to the lower end
of the temperature scale. System switch must be
placed in the OFF position. 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 rolls 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 gained
from your hands. If the thermometer pointer and the
setting lever indicator read approximately the same,
no recalibration is needed.
If recalibration is necessary:
1.
Place the temperature setting lever at the same
setting as the thermometer. Remove the cover by
pulling outward on right edge of cover until it snaps
free of the thermostat base.
2.
Insert 104994A Calibration Wrench (ordered
separately) onto the hex nut under the coil. See
Fig. 9. Hold the setting lever so it does not move and
turn the wrench clockwise until the mercury
rolls to the right end of the tube. Remove the wrench
and replace the cover.
NOTE:
To assure accurate temperature control, do
not touch or breathe on bimetal or ther-
mometer.
3.
Move the setting lever to a low setting. Wait at least
five minutes for the temperature to stabilize.
4.
Slowly move the setting lever until it reads the same
as the thermometer.
5.
Remove the cover. Hold the setting lever so it does
not move, reinsert the wrench and carefully turn
counterclockwise until the mercury rolls to the
left end of the tube, but
no farther
.
6.
Recheck the calibration. Set the thermostat system
switch for the desired operation and replace the
cover.
Fig. 9. Recalibration procedure.
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