Boiler or pipes and gurgling noise

[john brook]

Someone had a Worcester Green Star Ri boiler fitted in a small three bedroom terraced house about two months ago. The boiler is on the wall in the kitchen diner.

Every few days it makes a really loud * gurgle gurgle gurgle * noise which sounds like water sloshing about in the boiler or the pipework just above the boiler. Since its so loud and right-in the room, it can be very annoying.

Any idea what might be causing it and what might be done about it? Or is it just one of those things people have to learn to live with?

[The Natural Philosopher]

Bleed the air out of the rad circuits.

[Chris J Dixon]

Could it be the siphon dumping the condensate to drain?

The liquid accumulates until there is enough to initiate siphonic flow, and could presumably gurgle a bit once the level has fallen and air is sucked in, breaking the siphon.

Chris

[ARWadsworth]

It could be a poorly laid condensate run that is holding water.

[YAPH]

It could be condensate backing up into the boiler, though this would usually cause the boiler to stop working. Maybe it is somehow backing up into the boiler heat exchanger and then discharging? I'd check the condensate pipe run and maybe disconnect it and have the boiler condensate discharge into a bucket and see if the noise occurs again and, if so, if it's connected with condensate discharging into the bucket. Maybe the built-in syphon is partly blocked up?

The other possibility: this boiler is 'regular' or heating-only so probably on an open-vented system with a header tank in the attic. I'd check for pumping-over, and see what temperature the boiler's set to - could it be actually boiling?