Aprilaire 300 Owner's Manual page 5

The Water Panel, designed especially for uniform, high evaporation,
and the scale control insert (which encases the Water Panel),
effectively traps mineral deposits which are often the cause of
damage to working parts in ordinary humidifiers. The Water Panel is
the heart of the humidifier and must be in good condition to assure
high capacity trouble‑free performance. It should be changed at
least annually with the exception of Models 400 and 400M which
should be changed at least twice per heating season.
The distribution tray incorporates a synthetic fabric liner that is
designed to deliver water uniformly over the entire top surface of the
Water Panel, provided the humidifier is mounted level. It is normal
for some mineral deposits to form in the distribution tray as it dries
out between humidification cycles. These deposits can actually
help distribute water in the tray, but if they block the openings, they
should be removed as described in the PERIODIC PREVENTATIVE
MAINTENANCE section of this manual.
Your Digital Humidifier Control works in conjunction with your HVAC
system to control the operation of the humidifier. The control senses
indoor RH and outdoor temperature and automatically adjusts the
operation time of the humidifier to provide the optimum humidity
level in the home.
The Automatic Control can be set to turn on the HVAC blower when
humidity is required. Plumbing the humidifier to hot water is required
for this mode of operation.
The digital readout on the control displays the RH level inside the
cold air return duct. RH is a measure of the amount of moisture in
the air as a percentage of what the air can hold. Warm air can hold
more moisture than cold air can.
The control has lights which indicate humidifier operation, when the
Water Panel needs to be replaced and when service is required. See
OPERATING INSTRUCTIONS for more information.
There are many humidifiers on the market. They all add moisture with
varying degrees of efficiency. None, however, offer the features, design,
and performance incorporated into your new AprilAire Humidifier.
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