I posted a couple of weeks ago about Valliant 831. A quick recap, it had broken down in Jan and British Gas replaced 3 parts i.e., Diverter Valve, Expansion Vessel and Water Pressure Switch. We have a contract and paid the 50 excess. Because of cold spring the CH only went off a few weeks back and we discovered that the radiators still heated up when hot water was run for a few minutes. B Gas replaced the Diverter Valve yesterday and said the one that was fitted 4 months ago was sticking, we have obviously not been charged. After having showers this morning the radiators are warm. What is going on?