How the Dehumidistat Works
When using either the Two-Speed Switch with Humidity Sensor (435245) or the PrecisionSYNC Control (435244) a built-in
dehumidistat is present. The following information is provided on how it works.
High indoor humidity levels, during the heating season, have become a problem in many well insulated, tight homes. Excessive
condensation on the windows is a visual sign of high indoor humidity levels. High indoor humidity levels can result in mold, mildew
and the eventual degradation of the building structure itself. Your ERV reduces indoor humidity levels when the outdoor air is drier
than the indoor air.
These conditions usually occur during the heating season when outdoor temperatures are less than 59°F (15°C).
During the heating season, the operation of the ERV may reduce indoor humidity levels sufficiently to eliminate the need for further
dehumidification. Use the adjustable dehumidistat feature located on the control if your home requires further dehumidification
during the heating season.
The humidification function aggressively addresses high indoor humidity levels by initiating high speed ventilation when the indoor
humidity levels rise above the set point on the control. Once the humidity in the house is reduced, the ERV will revert back to its
previous setting.
It is recommended to operate the ERV for the first few days without use of the dehumidistat function to observe if a further
dehumidification effect will be required.
The dehumidistat operates in percentage of RH (relative humidity) with 60 being high and 20 being low. If after a few days, further
dehumidification is required (the building is still too humid), set the humidity level to a lower amount.
The average person is comfortable between 30% and 50% RH. The dehumidistat should be set to OFF for all seasons except the
heating season since a dehumidifying effect only occurs when the outdoor air is dryer than the indoor air.
Dehumidification Sensing
Every 6 hours the ERV will run and sample the outdoor air temperature (this includes when the unit is in Standby mode) to read
the outdoor temperature. The unit then resumes operations at the selected mode and speed (approximately 60 second duration).
Dehumidistat Disable or Dehumidistat Re-enable may be initiated.
Dehumidistat Disable automatically disables the Dehumidistat function on the main wall control when outdoor temperatures exceed
15°C (59°F) for a full 24-hour period. All other ERV features, and functions operate normally while the Dehumidistat function is
disabled.
Dehumidistat Re-enable automatically re-enables the Dehumidistat function if either the outdoor temperature drops below 15°C
(59°F) for a full 24-hour period or if the ERV is reset (unplugged for 30 seconds).
Residential Energy Recovery Ventilators
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