Hi, I have an old 3 story property with radiators on each floor. The radiators have become increasingly less efficient so feel flushing the system would have a hopeful benefit. I have bought a secondhand flushing unit (pictures attached) and would like some advice on how to set it up. Also, should I put some form of product in the system to break up the sludge before flushing. Any advice on setting up etc., would be much appreciated. Thanks, Terry