What could this noise be?!

[Applecakes987]

This is bizarre! Several days ago a noise started - it happens every few minutes and sounds similar to a car engine starting. It lasts several seconds. It’s louder at the front of the house. It happens day and night. It’s annoying and is disrupting my sleep.

I live in a flat, with flats above and below and next door, and can’t work out whether the noise is coming from inside the building or outside. I’ve gone to the window when it’s happening and can’t see any car or motorbike starting an engine. I’m fairly sure the noise is not coming from my flat, as it happens when I’m not doing anything - not turning on the taps or heating or anything.

I’m wondering whether something has gone wrong in the building and needs fixing (if so, what?!) or whether it’s something outside (but what?!?!). I’d be interested to know if anyone has experienced anything like this and worked out what it was!

Good grief, how annoying. This is going on all day?

It could be air in radiators or plumbing or perhaps a boiler itself fireing up.

Water hammer?

Yes, it’s going on all day - and night! I don’t think it’s a water hammer, as I’ve lived in places that had them and it doesn’t sound like that.

@Daftasabroom That’s an interesting thought. The ground floor flat in this building is currently being renovated - I wonder whether the work could have let air into the radiators or plumbing system? I’m on the second floor - don’t know whether the noise would travel this far from the ground floor?!

Is the heating system communal or is there one for each flat?

@Daftasabroom One for each flat (in that I have my own boiler, and when I’ve had new radiators put in, the water was drained from the radiator system in just my flat).