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VFD needed for 3-way valve system?
Our new HVAC system's chilled water system called for VFD on the chilled water pump. Our contractor, balancer, and control guy have never seen a VFD on a system with 3-way valves at the air handlers. In fact, the balancer needed all the pump had, just to get the right numbers. Was that expen$ive VFD necessary?