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of its mounting hole. Carefully lay the back edge of the hygrometer flat on the damp cloth.
Allow 30-45 minutes for the hygrometer to read approximately 95% humidity, If the
reading is not indicated, carefully rotate the coil by using a small head screwdriver counter
clockwise until the indicator hand is reading 95%.
Remount the hygrometer into the wood plaque. The hygrometer will gradually return to
indicate the actual condition of the air moisture content. IMPORTANT: Any other method
than what has been described to adjust the hygrometer could damage the instrument.
Dial Barometer
Acurite
®
barometers indicate barometric pressure by measuring changes in a small
chamber that has a partial vacuum. As atmospheric pressure varies on the chamber
and changes shape, it moves a small drive linkage connected to the indicator hand.
This linkage movement rotates the hand to register changes in pressure.
Unlike the thermometer and hygrometer instruments, the barometer is not affected
by location. Because all buildings have some air leakage, the atmospheric pressure
is the same indoors as it is outdoors.
The barometer has been regulated at the factory to function accurately at 950 ft.
above sea level. If the altitude in your location is different, the barometer must be
re-adjusted or reset using either of the following methods:
1. Contact your local radio/TV/internet weather service to get the correct barometric
pressure reading for your location. Now set your barometer to that reading by using a
blade screwdriver to turn the small adjustment screw located in the back of the
barometer instrument case. Turn the screw to the left or right until the indicator
hand moved in the direction you want. Continue to turn the screw until the indicator
hand is registering the correct pressure. Lightly tap the center of the lens to make
sure that the “adjustable pointer” is moving freely. This ensures that friction from the
linkage is not affecting a correct reading by the indicator. CAUTION: Be careful not to
force the adjustment screw. If the screw becomes tight in either direction, the end of
the adjustment range has been reached.
2. Use an existing barometer at your location which is known to be accurate and set
the new Acurite
®
barometer to the same reading using the same procedure as
outlined in step one.
The capability of a barometer to indicate changes in atmospheric pressure makes it a
valuable instrument in weather forecasting. You should take a reading at least once
daily, and always rotate the “adjustable pointer” to the exact location of the indicator
hand at the time of your reading. The “adjustable pointer” will allow you to tell what
changes in pressure have occurred since your last reading. Remember that the rate
of pressure change is just as important as the amount of change. This is why
multiple readings each day are best for accurate weather forecasting.
For the most accurate atmospheric pressure reading, it is a good idea to first lightly
tap the lens before checking the exact position of the indicator hand on the dial.
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Dial Thermometer
The dial thermometer is designed for indoor use only and will provide an accurate
measurement of air temperature in the vicinity of the instrument.
Dial thermometers are operated by sensitive bi-metal coil spring mechanisms that
respond to air temperature changes. The thermometer instrument has been
calibrated at the factory and should not need adjustment. As with all instruments
that are placed in a new location, you should always allow a period of several hours
for stabilization before determining whether it is reading accurately. Should you
determine that an adjustment of the thermometer is needed, this can be achieved by
using a small head screwdriver. On the back of the thermometer is a small hole
which will allow you to manually calibrate the temperature.
Insert the screwdriver head into the gold slot and turn clockwise or counter-clockwise
until the indicator hand is pointing to the known temperature reading.
Hygrometer (Humidity Meter)
Hygrometers measure relative air moisture percentage indoors. These instruments
operate by a sensitive coil spring that is bonded with a moisture absorbent material.
Hygrometers register the percentage of water vapor present compared to the
maximum amount that could be present at that air temperature. This is why the
instruments are also referred to as Humidity Meters. All air contains microscopic
water particles that are invisible to the human eye. If enough water is vaporized into
the air, the air will become “saturated”. This is considered to be 100% humidity.
The coils in hygrometers respond slowly and when humidity levels change abruptly, it
can take an hour or more for the meter to reach an accurate reading. Remember
that the hygrometer is reading indoor humidity, not the outdoor humidity as reported
by the weather service.
It is not uncommon to have low humidity readings during cold weather when indoor
air is heated. Humidity readings of 10% to 25% are typical where humidifiers are not
used to add water vapor into the air. The optimum humidity levels should be
maintained between 45% and 50% during heating seasons. Low humidity levels can
cause health problems and can be hard on wood furnishings.
Acurite
®
hygrometers are preset at the factory and typically should need no further
adjustment. Remember to allow ample time for the instrument to stabilize in its new
location before determining whether accurate humidity levels are being indicated. If you
do decide that the instrument needs re-adjustments, this can be done as follows:
Soak a folded face cloth or dish cloth with water and place the cloth on a plate, saucer or
another relatively flat container. Remove the hygrometer from the home comfort monitor
plaque by simply placing your hand against the back plate and pushing the instrument out
3 • How your home comfort monitor works
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