Hi all, I'm hoping someone can help. I moved into my home about 2 years ago in Las Vegas, where the humidity is pretty much non existant. One of the first things I did was have a whole house humidifier installed (Aprilaire 800 Steam Humidifier) and the thermostat replaced with a Honeywell IAQ. Every since then, no matter what setting I put the IAQ to, even AUTO/60% which is its max, my house ends up in between 20-32% humidity. My goal is about 40-45% due to some of the hardwood I installed (has already been destroyed once when the aprilaire's main circuit board fried itself, was dead for two weeks and I wasn't home). My HVAC guy couldn't figure out what the issue was so he offered to try putting the Aprilaire's humidistat in line with the honeywell, thinking that if the honeywell doesn't make a call for humidity for some reason, the Aprilaire's humidistat would as it operates more independent. That actually worked pretty well, until the humidistat stopped working (its now dead and Aprilaire won't replace it even though its under warranty), set the humidifier to run at max full time and I ended up with an A/C unit that was literally dripping water out of the ducting.

So, what I am trying to figure out is with the equipment I have, is it possible to get a stable 40-45% humidity in the house and if so, what am I doing wrong? As a last ditch effort I just disabled the outdoor temp sensor thinking the IAQ is doing some calculations or something. I'm pretty desperate at this point and have even purchased 2 free standing whole house humidifiers (put them in opposite sides of the house) and try to keep their tanks full trying to keep the % right but they run out of water so often that it doesn't really help.

My second question is that from what I am reading the IAQ will only make a call for humidity when its heating, and NOT when its cooling. That obviously is a pretty big problem when I live in the desert and its usually fairly hot outside...

Thanks for any assistance!