Lack Of Humidity - Aprilaire 220 Service Manual

WARNING:
120 VOLTS may cause serious injury from electrical shock on Model 110, 112,
1. 120 VOLTS may cause serious injury from electrical shock on Models 110, 112,
350, 360, 445, 760A and 760 humidifiers. Disconnect power and shut off water
350, 360, 445, 445A, 448, 760, 760A and 700 (Formerly model 768) humidifiers.
Disconnect power and shut off water supply before servicing or troubleshoot-
ing these units.
supply before servicing or troubleshooting these units.
2. Rotating or electrical components may cause serious injury from contact.
2. Rotating or electrical components may cause serious injury from contact.
Keep hands and face clear when checking operation.
Keep hands and face clear when checking operation.
3. Hot water temperatures in excess of 125ºF may cause burns.
3. Hot water temperatures in excess of 125ºF may cause burns.
CAUTION:
. Sudden operation may cause personal injury or property damage on Model
1. Sudden operation may cause personal injury or property damage on Models
220, 22x4, 440, 550A, 550, 560A and 560 humidifiers. Turn Auto-Trac™ Control
220, 224, 400, 440, 550, 550A, 558, 560, 560A, 568 and 600 humidifiers. Turn
System of manual humidistat to "Off" or lowest setting before servicing or
the Humidifier Control or manual humidistat to "Off" or lowest setting
troubleshooting these units.
before servicing or troubleshooting these units.
I. LACK OF HUMIDITY (All Units)
Check Relative Humidity Level In The Home
Aprilaire Humidifier Control – Automatic Mode
• The Aprilaire Humidifier Control supplied with the Aprilaire Automatic Humidifier can be used
to measure the relative humidity (RH) in the home. To determine the relative humidity in the
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
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 control "click ON". Next, slowly turn the dial counterclockwise until you hear
the control "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.
1
2
3
4
5
6
7
5. Return the thermostat and Humidifier Control to their original settings.
Aprilaire Humidifier Control – Manual Mode
• Follow steps 2 – 3, the point at which the solenoid valve opens is the humidity level in your
home.
Manual Humidistat
• The manual humidistat supplied with the Aprilaire ® Humidifier is an accurate gauge that
can be used to measure the relative humidity in the home. Turn the humidistat dial to the
lowest setting. Slowly increase the setting until a light click is heard. The relative humidity in
the home will be very close to the reading at this point.
Check Windows, Fans and Fireplaces — IT IS IMPORTANT THAT THE HOUSE BE
CHECKED FOR OPEN WINDOWS, EXHAUST FANS, AND FIREPLACE DAMPERS. They pro-
vide 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 you humidifier would not be
able to replace it even when running at full capacity.
Size Unit to House — The size home that can be satisfactorily humidified is determined by the
amount of outside air infiltration. The Air Conditioning, Refrigeration Institute (ARI) recommends
that home construction be classified in three general categories: loose, average, tight.
GENERAL SERVICE
(Table 2) % Relative Humidity Guide
Outdoor Temperature (°F)
-10 0 10
10 10 10
10 10 15
10 15 20
15 20 25
20 25 30
25 30 35
30 35 40
The Loose House — 2 air changes per hour.
The Average House — 1 air change per hour.
The Tight House — 1/2 air change per hour.
20 30 40
15 20 25
20 25 30
25 30 35
30 35 40
35 40 45
40 45 45
45 45 45
- 2 -
As an example, if the outdoor
temperature is 20° F and, follow-
ing step 3, the humidifier turns
OFF at "5" on the dial range,
then the relative humidity in your
home is 35%.