We had a Honeywell HE225A installed on our new construction after the contractor's hack put in an autoflo 200P model. We notice that when it is running, there is quite a bit of noise coming from the hot water line running to the unit. It sounds like there is air in the line or like someone left the faucet barely cracked open. I checked to see that the valve is open all the way, and it is. The humidifier/furnace is in our garage downstairs, and we can hear this upstairs on the opposite side of the house. Is this normal?