Trane Variable Speed Air Handler - setting fan speeds

How is changing the fan speed going to fix a very inadequate duct system?

I don't think the duct system is inadequate. If it is, it is certainly not "very inadequate." It was replaced a number of years ago. Inmstaller examin ed it at in stallation of new air handler and flet that it was just fine (so do I). Never had the air rush noise I am now experiencing. I think that lowering max fan speed would mitigate the noise - but would require longer run times - which is very acceptable. What I need to know is -- is this possible (lowering fan speed). Before I have any more discussions with my installer, I'd like to know what I am talking about (I always find that helpful).

although it is true dipswitches control supply air cfm, only your installer knows the specifics of your installation, including the old duct system. Who's providing the warranty on the equipment & install? Who's responsibility is it to satisfy their customer?

Was all new ductwork installed? Ducts sized to match the new air handler? Was upgrading the duct system not offered? Something you opted not to do?

There is only one person on this planet who can "see" your problem, that being the moron who installed it. Go to him for answers, because anybody else is guessing.

Dats nize

You did a heck of a lot of research before posting *NOT* there Patty Kakes. Google broke at your house? No? Oh just lazy.