A Trane XL14i heat pump was installed 6/8/05. The variable speed air handler fan only runs at full speed or off, but not slow when demand is low. The dealer's tech has replaced 2 electronic modules, to no avail. He can't seem get expert advice from Trane. I would greatly appreciate any advise to help him. Thanks in advance. BruceA

I think in some cases, you move wires or jumpers on the board. I am going to be looking at this on a couple of A/C units I care for.

Hi Labman,

Have you had a chance to check the units? Thanks again.

BruceA