Aprilaire 448 - Manual (Page 9)

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Additional Information
Be sure to keep fireplace dampers closed when not in use.
They provide an excellent escape route for heat, as well as
humidity. Humidity is lost at an even faster rate than heat because
water vapor tends to seek its own level and your humidifier would
not be able to replace it even when running at full capacity.
On occasion, indoor moisture producing activities such as
clothes drying, cooking, showers, etc., may raise the relative
humidity level higher than it should be, even though the Aprilaire
Humidifier is not operating. Telltale indications, again, are con-
densation or frost on cold surfaces such as windows, doors,
walls, etc. If such condensation persists for several hours, your
home should be ventilated to dissipate the potential damaging
excess moisture levels.
III. EFFECT OF WATER CHARACTERISTICS
Your humidifier will operate effectively using either hot, cold, hard
or mechanically softened water. Whether to use available tap water,
even though it may be quite hard, or chemically softened water, is a
common concern to homeowners when installing a humidifier.
Water used in homes contains varying amounts of minerals. The
residue remaining as a result of hard water evaporation is primarily
calcium and magnesium components and is usually quite hard,
scaly, and dense.
Residue from softened water tends to be soft and fluffy and has a
greater volume than hard water scale. The service life of a Water
Panel evaporator may be extended by using hard water, but in either
case, the Water Panel evaporator is usually changed once a year. In
the Model 448 Aprilaire Humidifier, these solids will build up on the
evaporator surface, in the reservoir and pump section. This is why
proper maintenance is important and necessary. Service hot water,
140° maximum, is recommended with drain type units for increas-
ing capacity and for heat pump applications.
In the drain-equipped models, most of these solids are effectively
controlled by flushing them down the drain.