Aprilaire 350 Owner's Manual page 8

TABLE 3 – Outdoor-Indoor Relative Humidity
Outside Temperature
+40°F
+30°F
+20°F
+10°F
– 10°F
– 20°F
Your Aprilaire Humidifier Control
is a precision instrument that
can be used to determine the RH
accurately in your home during
the winter.
To do this, follow these steps:
1. Activate the furnace blower
by setting your thermostat to
a higher temperature.
2. 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, read the RH on the dial. This will be very close
to the actual RH in your home. (See Figure B)
To check the humidifier operation, set the knob to "Test/Reset", make sure
that the water saddle valve is open and that there is electricity to the
humidifier. The furnace blower motor must be operating and the furnace
calling for heat for the Aprilaire Humidifier to function. Note: Turning the
knob to "Test/Reset" resets the "Change Water Panel" internal timer. In
addition, at this setting, the humidifier will only operate for 1 minute.
Reduce the humidistat setting to the recommended inside relative humidity,
depending on the outside temperature. DO NOT LEAVE IN TEST MODE
AS HUMIDIFIER WILL NOT OPERATE. Follow the suggested settings
prior to a drop in the outside temperature.
0°F
Recommended RH
FIGURE B
- 6 -
45%
40%
35%
30%
25%
20%
15%
90-1055