I have a new Carrier system with Infinity Control, installed six months ago. At the time, installer suggested leaving the fan running on low continually. Fine with me. As he was showing me how to do that, the "low" setting on the control worked fine, a very low, nearly inaudible blowing. Then he shut the system down to do something, and when it came time to run the "low" fan, it was running harder, louder, like medium. He said "it should settle down soon." And it did... eventually got back to a very low, quiet continual setting.
Now.. I turned the system off yesterday (switch at the unit in the basement) to check on filter. When I turned it all back on, I turned on the AC for the first time, as it's now hot outside. I'm trying to get the continual "low" setting of the fan to work again, but it's running harder and louder again--exactly the same sound/feel as the "medium" setting. And it's not settling down to low.
Any hints on what might be happening?