Boiler sounds like kettle that has boiled dry - help please

[ShesARumUn]

Afer having run a bath, the boiler started making a noise like a kettle that has boiled dry but can't turn itself off. Also a rather odd smell came from it - I would guess overheated pipes? I have now turned it off and left a message for a gas engineer to ring me. The noise has now stopped.

Does anyone have any experience/advice? Does it just need a service? Could it be time for a new boiler?? Is it dangerous? I have a carbon monoxide alarm that has not gone off.

Thank you

this is what is called "kettling"

It is usually caused by a layer of limescale or corrosion inside the boiler.

More noticeable when the boiler is turned up to higher temperatures, or the flame size is bigger (in cold weather with a modern modulating boiler)

If a combi, it can be quite difficult to remove.

If you have a cylinder, rather easier.

How old is the boiler?

How much limescale is in your kettle?

Is it a combi?

Does it have a pressure gauge on the front?

p.s.

If the radiators or the hot water were unusually hot, it is possible the thermostat has failed closed, or been turned to max. There is (if modern) a secondary stat to prevent it boiling.

When you said "boiler" you did mean a gas boiler, not a cylinder making the noise?

This is the boiler. I've taken a photo of the front panel, please see photo - it is still turned off so not sure if dials etc. are right?

I think it's a combi boiler and I think it's about ten years old or so. We do have a problem with limescale here (SE).

Not a DIY job. You could try turning it back on, setting any temperature controls on the boiler to low, so at least you will have radiators and hot water. If it is kettling I think you will find the noise will not be so loud when turned low. If either the tapwater or the radiators are scalding, turn it off until fixed.

Ok, thanks for your advice. I've turned the boiler on and down; all seems good so far. I'll wait to see what the engineer says.