My boiler cuts out after 30 seconds cutting off main gas valve so lose main burner and pilot. It had a new t/c a few weeks ago. The pilot will light ok when the main boiler lights it looks ok for 10seconds then pilot flame is jumping around all over the place so the t/c thinks pilot has gone out and cuts off gas. Sometimes it runs for a few days then does the above again. My be coincidence but is mostly windy when happens but first 10 sec seem fine which makes me think it is being starve of oxygen? Flue is clear and fins on heat exchange have been checked and cleaned.

Karl, October 2012

then make sure the case (and small cover around the pilot tube/thermocouple ,where they enter into the boiler)are both fitted correctly. or a flow of air,draught will exstinguish the pilot.

oops, October 2012

ooo a 45-60 BF (balanced flue ?)is the pilot burning sharp blue. 2 flames both like a bunsen burner.? if not the pilot block needs taking out , split the injector from the pilot, clean the pilot injector, reassemble.awkward, not difficult.

oops, October 2012