A method for preventing the gravitational back flow in a solar heating circuit has a motor operated ball valve in the flow and/or return pipe

摘要

A motor (18) driven pump (14) circulates water through a solar panel (16) and heat exchanger (12) primary (10) but restricts circulation when the pump is inactive by means of one or two ball valves (20,22) in the return (6) and flow (8) pipes respectively.