Noise coming from a Vokera gasoline boiler?

Qusetions: This is usually a unusual a single. I dwell in the block of flats. due to the fact the cold weather conditions has set in, the Vokera boiler inside the flat beneath mine may be releasing an everyday (and irritating) noise.

Every 3 minutes a rather loud humming style noise runs for fifteen seconds then halts; to become repeated.

Sadly, the noise can not be heard inside the flat with all the issue boiler.

Anyone understand what can be leading to this sort of a noise, and why this sort of a noise would drift as much as my residence (I was considering probably a block inside the vent for the exterior?)

PLEASE guide!

Answers:I would set revenue on it that its the fan. initial the 15 2nd purge and also the the ignition