It starts and runs for up to 30 mins and then cuts out completely with the contents very hot, then it won't start at all for 30-60mins. During this timw pressing the activate button gets no response at all. I have checked the exhaust pipework and it is clear and i have recently cleaned out all the ducts inside. I am happy to connect/disconnect gas appliances and also to replace parts but cannot identify the cause of the problem. Any suggestions appreciated...

Jack Philips, September 2020