My wife and I recently purchased a home with two heat pumps in installed 6/05/05. The down stairs unit makes noise like a jet taking off. I asked the installer if we could slow the air volume down and he responded by saying the factory settings were not changeable. These were state of the art when the install was done.Model # of the down stairs unit is TWE065E13FB2 and the owners information indicates the blower speed is variable. What do we need to do to slow down our blower?

There should be set pins, (dip switches on the control board for changing fan speed. Do you have the instulation manual?