I work for a large company that does alot of carrier infinity zone systems and the person who designs them I think is under sizing the zones because alot of them have noise. They asked me to work on one house it has three zones two dampers per zone and have mixed both the new dampers and the old comfort zone dampers. first of all some times iam getting funny noises from the dampers i think there is too much load on the 40va transformer in the furnace and the dampers are not working properly because also iam getting a failer on my second and third saying airfow limit exceeded. is it improper duct size or an overload on the transformer and the dampers are not opening causing the varible speed to ramp up????