Boiler burner stopping / starting

[JonathanTaylor]

When I woke this morning there was no hot water. The controller was set for hot water on, but the boiler was not doing anything. The lockout light was not lit, but I pressed it anyway. It then clicked into life and went through the process of clearing out the existing gases, then lighting the flame. The flame then burned for about a minute, before a click (maybe several quiet clicks, hard to tell) and it stops burning. A few seconds later there is another click and the burner restarts following the same pattern as above. It repeats this a few times, before eventually stopping the cycle and not even trying to fire. The lockout light does not light up. The boiler has been burning (it feels warm) but the water is not up to temperature yet (the boiler has only run for perhaps 5 mins). About 5 or so minutes later, it then kicks back into life and the process above repeats.

When it's working OK, I think it just burns until the water is hot, rather than this on/off process. I have cleaned the photo-cell as it does tend to soot up (that cell was also replaced at the last service, completed around 6 months ago I guess). Boiler is an Trianco Iona brand. Any ideas?

Edit: Whilst it is in the phase where it is burning, the plastic box that houses the lock out switch (and a load of other stuff) is also making clicking noises - not sure if that is normal.

 

[oilhead]

If the photocell is sooted up after 6 months, then get the rest of the boiler cleaned out. The stop/start is due to flame lack of flame sensing, probably because the flame is hindered by the clogged up passages through the boiler. The Iona is a Eurostar by any other name and suffers in the same way.

 

[Boilerman2]

If balanced flue the root cause could well be a failing seal on the discharge duct, contaminating the air inlet duct - Trianco balanced flues are renowned for it!

 

[JonathanTaylor]

Cheers chaps I had an engineer out this morning who checked the photocell (the one that was replaced 6 months ago) and he noticed signs of deterioration - as if the outside of it was not able to withstand the heat inside the burner unit), so he swapped in a new one...problem solved. He did a few other checks and had a good look around, so hopefully it's just this component that was the root cause too..

Coming to the conclusion this Trianco boiler is a heap of junk (he concurred), so I took a handful of photcells to just swap them over as and when they play up.

Thanks for taking the time to answer