The unit had two ways to install: place the unit on the supply side or the return side with the by-pass duct running to the opposite side. Due to space reasons I had to place the unit on the supply side. I made sure the humidistat was above the by-pass duct entrance on the return side.
To me it seems that with this setup not much of the humidified air would ever get to the rest of the house, due to this recirculating air pattern. Any suggestion? Thanks for all replies.