Honeywell T498A - Manual (Page 5)

T498A,B ELECTRIC HEAT THERMOSTATS
95C-10686—3 5
CALIBRATION
The T498 Thermostats are calibrated at the factory using
precise instruments under closely controlled conditions.
Recalibration should not be necessary. Allow the thermostat
to operate for several hours before checking calibration.
Temperature deviations of 2
° F (1 ° C) are normal. If the
thermostat is mounted in a suitable location and still appears
out of calibration, check calibration using the procedures that
follow.
Check Calibration
ᕡ Remove the thermostat cover and set it aside for
several minutes. Radiant heat from your hands will
affect the thermometer reading.
ᕢ Turn the setting dial clockwise until the switch makes
(clicking sound) and the heating equipment and fan
start.
ᕣ No recalibration is necessary if the thermostat switch
makes with the thermostat setting at the same
temperature as indicated on the thermostat cover
thermometer.
ᕤ If the thermostat setting differs from the thermometer,
record the temperature difference and recalibrate as
instructed in the Recalibration Procedure section.
Recalibration Procedure
ᕡ Note the temperature difference between the
thermostat setting and the thermometer.
ᕢ
Turn the setting dial clockwise until the switch makes
(clicking sound).
ᕣ Remove the adhesive backing of the indicator decal
provided.
ᕤ Carefully align the indicator mark on the decal with the
correct temperature setting number on the cover. See
Fig. 6.
ᕥ Using finger pressure, secure the realigned decal on
the center of the knob.
ᕦ Wait five minutes and recheck the calibration.
40
5 0 60
7
0
8
0
OFF
°F
50 60 70 80 90
M7237
APPLY NEW INSERT DECAL
Fig. 6. Thermostat recalibration.