Gas fire keeps "cutting out"

[Jethro_uk]

We've had a gas fire (2nd Hand) in the lounge for 10 years now. Properly fitted by a corgi fitter, who fitted a flue liner (or something) and mounted it into the fireplace.

Of late, it's started "cutting out" after about half an hour, it's roaring away on setting no. 2 (the one we use most) and then just stops and goes back to a small flame. I'm guessing the flame sensor is flaky, and it thinks it's lost the flame, so chokes the gas ? Is there anything I can clean, or check the adjustment of, or is it straight to a GasSafe fitter ?

[Owain]

Or it might be an oxygen depletion sensor stopping the fire from killing you.

If it hasn't had a service including a flue check for the last 10 years I'd suggest treating it to one. At one a year, a decade can add up to a lot of birds' nests.

Owain

[Dave Liquorice]

A "coal effect real flame fire" burning gas and shoving most of the heat up the chimney or a gas fire with incandescant fire bricks?

[harry]

You could be right about the flame sensor/thermocouple. But usually they wont light up at all if the thermocouple is US. You can get them pretty easily, there are universal ones that fit most things. But if it has never been serviced in ten years there are lots of things that will need cleaning out. It could even be dangerous. The flame could be "lifting off" if the gas/air ratio is wrong through some kind of blockage.