my ferroli optima boiler has stopped working hot water is fine but sometimes heating will not fire upone night it was working and then whentemp reached failed to come back on sometimes starts and then other times wont engineer been out but cant see anything wrong
When I decorated my hall (took the old ceiling down) lots of dust got in the wall mounted room stat through the air holes - the heating became intermittent. I took the stat off the wall and cleaned it up - testing the contacts with a multimeter showed they were the cause - sometimes they worked but not always - just guessing.