We are in a brand new house with a brand new Bryant 3 zone Furnace for 4200 sq feet. The folks who installed the system have been out 13 times to fix variuos issues from it freezing up to crossed wires on the dampers. Now it is creating a high pitched whistle when I turn two zones cooler than the third at night. They have sugessted creating an out zone in the basement to regulate the air flow, but have said it will be difficult to control the temp in the basement which we eventually want to finish. Am I getting good advice? I feel that we may have a lemon. Thanks for any input!

Did they install a bypass damper at the furnace? Ths damper connects the supply and return plenums together and is usually regulated by a weight.

There is something attached that looks like a long silver rod with a circular weight at the top - is this what you mean?