Worcester Greenstar 28i making clunking noise on CH and HW

[Lucci]

Hi there,

I have a Worcester Greenstar 28i combi boiler which is making a kettling noise (clunking noise) when turning on CH or hot water. It started today. Hot water was working fine this morning, (although there was also a bit of unusual noise) but it now stopped as well. The reset button blinks red after some time, which I press and hold for a while and then it goes away.
I have checked the overflow pipe for blockages but it is fine. We live in a hard water area and I think it could related to limescale somewhere. We had the same noises and no CH in the winter but it turned up to be ice in the overflow pipe.
I made a video showing the noise:

Any ideas?
Thanks in advance.

 

[ianmcd]

sounds like the condensate is blocked and backing up into the heat exchanger

 

[Lucci]

Ian,

Exactly like you said. The condensate transparent container was blocked. I removed it, cleaned it and it is working beautifully now. Appreciate your help mate.