Is there any linkage between when an Ultra–Aire model runs ventilation, and when it runs the dehumidifier? Is such a thing possible or practical? The benefit as I see it if the dehumidifier were made to run during the time ventilation was called, then there would be no humidity load added to the house. In some situations, however, it might mean running the dehumidifier longer than would otherwise be the case. There would be some energy cost too (I’m enough of an admirer to gladly pay the energy cost).
Just brainstorming, I suppose a 2nd humidity sensor inside the fresh air duct might guarantee such a linkage. Probably there are other and better ways…
Best wishes — MRJ
Usually, operating the dehumidifier when the inside %RH exceeds the inside preset dehumidistat setting is the best strategy for minimizing dehumidification. There are many hours/days that fresh air ventilation humidity is removed by the a/c operation. Operating the dehumidifier on those days would mean extra cost and over-dry your home. There are several possible variations in activating the dehumidifier. Sensing the combined air streams of outside fresh air and/or inside dehumidifier return air is a possibility. Typically, when the a/c is not operating, the dehumidifier will sense the rise in %RH from high outside moisture and operate while the ventilation is operating. Better to provide fresh air when the home is occupied with extended ventilation times. Avoid short cycling of the dehumidifier and a/c for best dehumidification.