Aprilaire 400 Owner's Manual page 7

The relative humidity in your home
will now be accurately controlled to
meet your needs and should not
need further adjustment during
future heating seasons. Make note
of the dial setting in the event you
temporarily move the knob when
performing annual maintenance of
the Aprilaire Humidifier.
Your Aprilaire 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
RH in your home, follow these steps:
1. Determine the outdoor temperature.
2. Activate the furnace blower by 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 on the humidifier "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 Humidifier Control to their original
settings.
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.
FIGURE A
5
4
3
AUTOMATIC MODE
1
/ %. If you would like to determine the
2
- 5 -
7
6
2
1