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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
unit. 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. After the
humidifier has operated for one minute and water is entering the unit and
coming out at the drain, 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.
TE
ST
/
RE
SE
T
O
F
F
MANUAL MODE
%
H
U
M
ID
IT
Y
2
5
%
15%
3
5
%
45%
O
U
T
D
O
O
R
T
E
M
P
E
R
A
T
U
R
E
0
°
F
2
0
°
F
40
°
F
FIGURE B
TABLE 3 – Outdoor-Indoor Relative Humidity
Outside Temperature
Recommended RH
+40°F
45%
+30°F
40%
+20°F
35%
+10°F
30%
0°F
25%
– 10°F
20%
– 20°F
15%
