Aprilaire 400m Humidifier User Manual


 
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WATER PANEL CHANGE INDICATOR
The control keeps track of humidifier operation time. The yellow “Change
Water Panel” light flashes after a preset amount of running time has
elapsed. This running time is preset by the installer based on the humidifier
model and water characteristics.
Refer to the Annual Maintenance section for instructions on changing the
Water Panel or call your heating and air conditioning dealer for service. After
the Water Panel is replaced, turn the Control knob to the “Test/Reset”
position until the green “Humidifier ON” light flashes, to reset the Water
Panel change timer.
TEST/RESET
The Test/Reset feature allows the humidifier operation to be checked even if
there is no call for humidity. See “Check the Humidifier Operation” on page 9.
ADDITIONAL INFORMATION
Your humidifier is a precision system that will accurately maintain the RH in
your home. For every 2°F change in outdoor temperature, the Digital
Humidifier Control will automatically adjust the indoor RH by 1%.
The Digital Humidifier Control will accurately control the humidity in your
home to a maximum of 45% RH and a minimum of 10% RH.
The RH Values in Table 2 are targets based on outdoor temperature and the
Digital Humidifier Control setting. The actual RH may vary due to conditions
in the home (cooking, showering, etc.).
TABLE 2 – % Relative Humidity Guide
Outdoor Temperature (°F)
-10°F 0°F 10°F 20°F 30°F 40°F
1 10% 10% 10% 15% 20% 25%
2 10% 10% 15% 20% 25% 30%
3 10% 15% 20% 25% 30% 35%
4 15% 20% 25% 30% 35% 40%
5 20% 25% 30% 35% 40% 45%
6 25% 30% 35% 40% 45% 45%
7 30% 35% 40% 45% 45% 45%
Dial Setting
Relative Humidity (%)
MANUAL MODE
When installed in the Manual Mode (see Figure B), it is important to
anticipate a drop in outdoor temperature and reduce the setting accordingly
to avoid excessive condensation. For example, with an outdoor temperature
of 20°F the correct setting will be 35% RH. If the temperature is expected to
fall to 0°F that evening, then merely reduce the setting to 25% several hours
prior to the temperature change.
See Table 1 for the recommended settings. These settings, which are based on
years of research, represent a compromise between RH levels that would be
most desirable for comfort and humidity levels that are suitable for protection
of your home and to avoid condensation on your windows. For example, a
wintertime indoor RH of 50% may be considered ideal for comfort, but
unfortunately, it probably would result in condensation, which can cause
damage to your home. Observing the recommended RH levels on your
Humidifier Control is an important safeguard. Condensation of water on the
inside surface of windows in the form of fogging or frost is usually an indication
of too much RH. This same condensation can occur in other areas in your
home, possibly resulting in damage.
FIGURE B – Manual Mode
90-1236
TABLE 1 – Outdoor Temperature/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%
Manual Mode
Label and Resistor