I have an Ocean Alpha 240p which is giving me a lot of grief. It started by being erratic in supplying DHW and then stopped completely, but the pilot is still on. My CH is currently off. I followed the installation manual procedures for fault finding and all worked well until the "Air pressure switch proved" stage where the neon remained illuminated. The recommended action is to replace the air pressure switch, which I did. I then tested the DHW with the room sealed chamber panel off and everything worked fine. When I replaced the panel, the burner went off and no DHW was supplied anymore. I removed the panel and the boiler worked fine again. Closed the panel and problems were back again. I took off the fan assembly and cleaned the flue and put back everything. Boiler worked for a few hours and has stopped again. Could anybody help as to what the problem could be and how to get around it? Many thanks.