Hi. Our Potterton Performa 24 was working, seemingly, without any issues for the 3 years we've been in this house. My other half drained the CH and moved the radiator in one of the bedrooms before repressurising. Since then the central heating pressure slowly creeps up and within 10 minutes or so it's at 3 bar. I wasn't paying attention once and caught it at nearly 3.5 bar. I've checked when it was slightly over 3 and water slowly drips out of the overflow outside at a rate of about one drip per second, if not slightly slower.
It was like this for a few days before we bled the radiators again and now when we run the hot tap the water will work for about a minute and then the flame goes out for 10 seconds or so and reignites and the cycle continues. The water doesn't get much chance to get anything other than warm. There is a rumbling/groaning sound that lasts for 3 seconds or so either just before or just after the boiler going going off, I can't recall which. If we run the tap slowly the groaning sound is not as loud but still as periodic, the water is hotter and it doesn't shut off.
What do you think might be wrong please?
