Worcester Bosch Greenstar knocking noise

[tchiscilo]

Hello, I have just moved in to a new flat this week and have a problem with noise coming from somewhere around the top of the boiler.

It's a loud clicking/knocking sound that lasts about a minute, stops for 20-30 seconds and starts again. It seems to happen at night, starting in the evening, and got pretty bad at 3am last night. I switched the boiler off completely and it continued for about 3 hours after that.

I have a video of the noise it makes: youtube.com/shorts/EgtfGtKBawA

It's a Worcester Bosch Greenstar 241 Junior.
Would anyone happen to know what might be causing this? Thank you.

 

[tchiscilo]

I have found the issue, which is not coming from the boiler itself. Some leaking water is dripping from one of the flats above mine from their flue onto mine, creating the loud echoing sound.