Fan Speed

Can someone tell me how to adjust the fan speed on a 10 year old Trane XL80 mid efficiency unit? Is it done with dip switches? or?

Thanks

Moisheh

Get the install manual for you furnace. I'm not sure that a 10 year old XL80 is a "mid efficiency" unit. I think it is a basic 80% efficient, with a multi-speed motor, not a variable speed motor. A quick look at the motor itself would probably confirm.