I recently had a 3.0 ton Trane xl16i system installed in my home. The new air handler is set to 350 cfm
The old system was a 2.5 ton and had a single air return which is a 20" x 30" filter with a 14" flex duct.
When I had the new system put in, I added 3 new 12" x 12" air returns for each of the 3 bedrooms the unit services. The obvious purpose was to get more air circulating in those rooms and allow the hot air to escape.
So now I have 4 air returns on the system.
I want to restrict the flow of the 20" x 30" air return to encourage more air to be pulled from the 3 new air returns located in the bedrooms.
My question is:
How much would it be appropriate to restrict that 20" x 30" air return and still not starve the air handler of return air?
Any help would be appreciated!