eVerYDaY
operation
what should my humidity setpoint be? • The outdoor air temperature affects how much humidity can be
retained by the air in your home. Use this table as a starting point. Then adjust the humidity control to your
own comfort or until condensation appears on the windows.
what is a frost setting?• Some humidity controls (such as Prestige, VisionPRO IAQ, and True IAQ) contain
a Window Frost Protection feature which limits humidity output based on outdoor conditions. For example,
on colder days, the air in your home can hold less humidity. The humidity control automatically lowers the
humidity setpoint accordingly, to prevent frost from appearing on the inside of your windows.
Lower the frost setting by one value each morning that you see frost or condensation on windows. Allow 24
hours for the new setting to take effect before re-adjusting. Once you have this set to a comfortable level
without condensation, you will not need to adjust further. You can adjust your humidity setpoint without
worrying about condensation.
Manual humidity controls (such as the H8908) do not have built-in frost settings. They require you to adjust
the humidity setpoint when the outdoor temperature changes. Use higher humidity setpoints when the
temperature is warmer, and lower setpoints when the temperature is cooler.
outdoor recommended relative
temperature Humidity setting
-20°F (-29°C) 15%
-10°F (-23°C) 20%
0°F (-18°C) 25%
10°F (-12°C) 30%
20°F (-7°C) 35%
>20°F (-1°C) 35%
M27982
TrueSTEAM Humidification System 69-2286EFS—03
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