Aprilaire 448 - Manual (Page 5)

II. OPERATING INSTRUCTIONS
There are 2 possible modes of operation of your Aprilaire Humidifier
Control and an explanation of both modes follows:
Automatic Mode:
(Manual Mode-see pg 5)
Your Aprilaire Humidifier Control is installed in the cold air return.
During the first heating season, your Humidifier Control needs to
be set initially to match your home’s condition. Please follow these
steps when adjusting your control (refer to Figure A).
1. Turn the dial setting knob to “5,” which is within the normal range.
During the next 24-48 hours it may be necessary to adjust the dial for
more or less humidity, depending on your personal comfort and
home’s requirements. Refer to the “Operation Guide” (Table 1).
2. During the coldest portion of the first heating season, minor
adjustments may be necessary. This is dependent upon your
individual home construction, refer to the “Operation Guide” (Table 1).
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(Table 1) Operation Guide
Condition Solution
Condensation on windows Reduce the setting on the control dial
by 1 increment.
Lack of humidity Increase the setting on the control dial
by 1 increment.
Humidifier does not operate Turn dial to “Test.” Make certain furnace
blower is operating and furnace is calling
for heat. If unit still doesn’t operate, consult
a heating contractor.
Humidifier won’t shut off Turn dial to “Off.” If unit continues to
operate, consult a heating contractor.
Test mode System operation is checked by setting the
knob to “Test.” Make certain furnace blower
is operating and furnace is calling for heat.
Humidifier will operate for one minute.