Something Going Bump.......

[Mosaic]

Now here's an oddness. I've noticed when I run the hot tap in the kitchen, I can detect a very low, almost subsonic bumping noise. Seems low down ie below counter level. Doesn't seem to happen with the cold tap and doesn't appear detectable in the rest of the house. Combi-boiler system.
Do you think someone's trying to get my attention?
Any offers of advice gratefully received.

[Teddio]

It's probably the gas meter. When a large volume of gas passes through the meter it may emit a low frequency bumping noise which id transmitted along the gas pipe.

[The Builder]

That's interesting. I wouldn't have thought of the gas supply.

Otherwise, it's only on the Hot Water, so it may be in the Combi. Possibly the diverter valve which allows water to either the CH or the HW, depending on which is selected. Perhaps it's "bouncing" slightly.

Put your ear to the boiler next time it happens, to see if anything is apparent.

[Mosaic]

i will work towards that Builder - will need to instruct OH as the boiler's in the garage.....captain to engine room....

[Mosaic]

And I will double check Teddio, as your suggestion of gas involvement makes sense as the combi ignites when the hot water runs.

[Teddio]

Mosaic, I should have said, turn the hot water on and put your ear near to the gas meter.