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VENTURI with Hydronic wall radiators
I have an 1940 2100 sf home built very solid with 8 inch cement floors The old oil boiler has been removed and being replace with 3 separate gas boilers The old system had a venturi system using steam radiators as the convection. It had 1/2 inch lines coming of 1 inch feeds and returns I am planning to install 3 separate loops. Should I replace everything with 3/4 pex or can I use most of the existing piping which is a hodgepodge of 1 inch and 1/2 inch. I am thinking 1/2 inch with 3/4 should be ok . Presently 1/2 inch is going to the radiators. I am wondering how much of the 1/2 inch can still be used. I prefer to keep everything 1/2 inch. or should all the pipes ideally be the same diameter on a closed loop.