We seem to have had an endless line of problems with out combi boiler this past month. We thought all the niggling issues had been resolved but today the burner just locked out. I reset it hoping it would work but it wouldn’t fire.

After a bit of investigation i discovered that the feed if oil stopped. We have half a tank full so no issue there. The pipe was all sound, no damage or kinks etc. So I managed to draw the oil back through into the burner and got it firing again. Then after about an hour it stopped again. Same problem. So I rechecked the feed pipe again and the only thing I could find was that one of the right angled connecters was very slightly loose and was letting a very small amount of oil to leak from it. So i tightened it up to get it sealed, got the oil running back into the burner and it fired up again.

An hour later it’s still running but i’m constantly checking to make sure the burner doesn’t lock out again. So can a small leak in the oil feed line cause the feed to slow or stop? Other than this issue the boiler is running fine.

If it’s a two pipe or tiger loop instal then a leak on a suction line will draw air in.

I would check the filter though as it sounds like it could be choked. Boiler locks out, allowing oil filter to fill, but when boiler firing it draws the oil quicker than it is supplied, usually runs for the length of time it takes to empty the oil line.

Or could be the solenoid coil breaking down when it gets warm.