To prepare for winter I wanted a power flush to a central heating system well over 30 years old, upgraded with a new boiler and thermostatic valves 10 years ago, but now known to be sludged up. In fact we found the system was on its last legs. David flushed the system and each individual radiator, working methodically to deal with various problems which showed up: un-sticking radiator valves and replacing a faulty one, clearing blockages, soldering a new radiator joint, replacing isolating valves which didn’t work properly, getting a three port valve to work again and replacing a failing pump, as well as contacting the boiler manufacturer because despite annual servicing by British Gas it appeared to have overheated. Unusually high amounts of sludge and scale were removed. Six months on, the system remains fault free, the radiators have no cold spots, the pump is quieter, and the boiler provides the same heat on lower settings. A bigger job than either of us expected, but well worth it.