I am having a problem with a vokera option 24.A week ago, the boiler ceased to work completly.when calling for heat the pump would run but the fan would not operate.Strangely,there was only 190V going to the fan so I replaced the board.Now the boiler fires for about 10 seconds and then cuts off,not to lock out though as it comes back on a fewe minutes later only to do the same again.The flow pipe becomes untouchable just before cutting off as does the pump however the return can sometimes be lukewarm and sometimes as it should be.I checked for blockages at the heat exchanger, pump and internal bypass though could find nothing.The radiators all heat well apart from the furthest away one in the living room.I went under the floor to check how far the pipes were heating and for any kinks in the hep20 pipe but found that the pipes are warm for most of the main run before becoming lukewarm near the end.I have tried everything,drained the system and flushed it through a few times but to no avail,the boiler just keeps overheating and cutting off.Hot water works fine so I think it is definetly blocked somewhere.Any ideas whatsoever would be greatly appreciated as I spent all day today trying to figure it out!!!
