Unvented system noises

[ianshep]

THere have been a few similar questions - but so far none seem to fit my customers problem. 1 year old unvented system. Was fine for over 9 months then noises started on drawing off water from some of the taps. Best described as a deep groaning noise which goes on for 10-15 secs. Seems to come from the area of the valvework near the cylinder but difficult to tell. Only ooccurs from time to time but no particular circumstances seem to prompt the noise.

What should I try? Expansion vessel? Could the pressure have been lost in the uppper (air) part? Could it be the presuure reducing valve vibrating? All the pipework is well fixed.

Becoming very annoying as without some idea of the cause it is not easy to convince more work is required!

Thanks for any ideas

Unvented cylinder is an Albion Ultrasteel

 

[Megaflo-Experts]

Does it happen when you draw off hot water only or either hot or cold?

Sounds like something to do with the inlet, so possibly the PRV, which may have a filter that needs cleaning out.

 

[Nat]

Check the pressure of the expansion vessel is correct.

 

[BLOD]

Measure the static and dynamic pressure at a hot outlet and set the exp vessel pressure to about half way between, & see if this helps.

 

[kimbo]

I had same problem with a megaflo. I phoned them and they told me it was the check valve in the combination valve. I changed it and all was well. Ring the manufacturers it should be under warranty if none of the other things mentioned work.