I have a potterton central heating system. My timer switch has broken and I need to repair it. Its an old timer switch EP 4000 and I have been told that they do not stock it anymore and it has been replaced by the EP 4002. Does anyone know if this is true because I have looked on the internet and you are still able to puchase an EP 4000. If it has been replaced by the 4002 then is the wiring still pretty much the same? Many thanks.