Honeywell VP IAQ, Maytag heat pump system, arzel zoning, Maytag/Venmar ERV, truesteam humidifer, tight house.
IAQ is set to humidify at 40% (Frost protection 4), dehumidify at 50%.
Except on exceptionally cold/dry days, indoor humidity stays at 40-43% without humididfication.
I'm trying to understand "when" the IAQ decides to run the ERV to attempt dehumidification in the winter. How far over the humidification set point does it let it rise? What is the slope of the calculated set point reduction (based on OAT and frost protection level)? We have noticed some condensation on the windows (Andersen 400 low-e/argon) in the lower corners of the panes (spots smaller than a dime, but still there) on cold nights (<25 degrees OAT). It appears that the IAQ is running the ERV on high to try and bring humidity below 40% (I've noticed it get it down to 38% so far...). But maybe it's just the timed ERV cycles running and the IAQ is just not running the humidifier (letting the house "dry out" on it's own)? I would really like to understand the logic it is using so we can tweak the settings and get rid of the condensation without over ventilating.