Zoning a HVAC System - Ducts under slab
We just moved into a new house and have a problem with the forced-air heating system for the bedrooms (separate from the rest of the house). The master gets most of the air flow and the other two bedrooms get very little, so they are cold most of the time.
The HVAC contractor says solve the problem by closing vents in the master. Even with all these vents closed, the other rooms still don't get very warm; besides, the whistling air from the closed vents is VERY noisy.
The ducts run under a slab on grade, and the contractor says he can't zone the system now, as I would like to do. He says the ducts don't separate until they are under the slab.
Does anyone know of a solution or products that address this problem?