Aprilaire 220 - Manual (Page 6)

Your Aprüaire Automatic Humidifier, is a high precision system
that will accurately maintain the relative humidity in your home.
For every 1° change in outdoor temperature, the control will
automatically adjust the indoor relative humidity (RH) by
/?%.
If you would like to determine the RH in your home, follow
these steps:
1. Determine the outdoor temperature.
2. Activate the furnace blower by setting your thermostat fan
switch to the “On” position, or setting your thermostat to a
higher temperature.
3. Turn the control dial setting to the “Off” position. Then,
slowly turn the dial clockwise until you hear the solenoid
valve “click on.” Next, slowly turn the dial counter
clockwise until you hear the solenoid valve “click off.” At
this point, make note of the dial setting.
4. Locate your dial setting on Table 2. Follow the dial setting
to the right until it intersects with the current outdoor
temperature. This is the relative humidity in your home
under existing conditions.
5. Return the thermostat and the control to their original
settings.
(Table 2} % Relative Humidity Guide
Outdoor Temperature (°F)
O)
_c
03
CO
b
-10 0 10 20 30 40
1 10 10 10 15 20 25
2 10 10 15 20 25 30
3 10 15 20 ;:2&:. 30 35
4 15 20 35 40
5 20 25
Ml
40 45
6 25 30 35 40 45 45
7 30 35 40 45 45 45
As an example, if the outdoor temperature is 20^^ F, and, following step 3, the
humidifier turns off at “5” on the dial range, then the RH in your home is 35%.
The Automatic Humidifier will accurately control the humidity
in your home to a maximum of 45% RH and a minimum of
10% RH. The values of outdoor temperature and dial settings
may fall in between or outside of the listed values in Table 2. In
these cases, you can only approximate your home’s actual
indoor RH.
4-