I have a Suprima 70 which I suspect has a dodgy PCB. With the boiler stat set to about one third of maximum the boiler seems to run OK. If I wind it up to about two thirds it runs fine (sometimes for days), but intermittently I get banging from the boiler (water in it vaporising?). This seems to be worse when the boiler is only heating the HW but it does happen on CH or both as well. I have found that immediately after this happens (and I suspect just before), the pump has stopped running. I have confirmed with a meter that there is no power to the pump at this stage. The boiler does not lock out and will start up again with pump running after a minute or two. I have had the PCB out and inspected it with a magnifying glass and can see no sign of dry joints. Can I safely assume that the PCB is faulty or do the experts here have any other suggestions before I fork out the cash.