I have vaillant ecotec 624 boiler ,heating is working ok but hot water runs hot for about 2mins then runs cold if you leave it for about 5mins its hot again help ???
blocked ventura.take the boiler cover off and remove the heat shield this will allow the boiler to breath.ask for hot water and see if the boiler remains lit.if it does that's your answer.if still has the same problem suspect thermistor/high level T/stat
ozone
December 2011
blocked heat exchanger
A1
December 2011
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