Aprilaire 448 owner manual Automatic Mode Manual Mode-see pg, Operation Guide

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).

(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.

- 3 -