Noise Coming from DHW Expansion Pipe

[pbroddle]

Hi folks,
have an Istor HE325 boiler in a new build. Most problems sorted but 1 remaining... After the boiler has been on for hot water when the first tap is opened to get hot water a very loud vibrationary noise comes from the boiler. On further inspection the pipe from the DHW Expansion Vessel was vibrating and as this stopped vibrating so did the noise.

This is perfectly reproducable so is a constant source of annoyance. I have had engineers out to see the issue and the best they have done is to lag the pipe with insulation.....still the same vibration and noise just doesn't clatter against the front cover of the boiler which it didn't before as I had remove it.

I guess it's some kind of air lock but I have no idea how to get rid of it. Any ideas welcome.

Thanks, Paul

 

[namsag]

As opposed to boiler the fault is probably the ball cock in your hot water tank in the loft , water hammer and vibrating right through pipework , try changing it

 

[pbroddle]

Namsag,
there is no hot water tank in the loft & therefore no ball cock. It is a condensing boiler with an unvented DHW cylinder combined in a single unit, hence the expansion vessel.

Cheers, Paul