Unvented System - Noise Issue

[monkeydust]

Anyone know what might be causing this situation please? We have replaced the EV and non-return valve but still happens.

Normal static pressure on that gauge is 2.5 but it builds up overnight to 3+ and then the problem occurs.

Were a bit lost and had a few engineers look at it.

At this point if someone helps me out and solves this happy to send over some beers (money) your way!

 

[Ben-gee]

You say it builds up pressure overnight- is the cylinder being heated during this period?

 

[monkeydust]

You say it builds up pressure overnight- is the cylinder being heated during this period?

Hi, yes it is.

 

[PETE 123]

Temp or pressure build up overnight test temp by turning off hot water control and emersion.

 

[monkeydust]

Temp or pressure build up overnight test temp by turning off hot water control and emersion.

Yes I can try that, if this is the issue and I have a strong suspicion it is then what is the solution or next step ? Txs

 

[Ben-gee]

If turning off the heat sources to the cylinder solves the problem (try it a few nights), report back.
If it doesn’t solve the problem, report back.

 

[monkeydust]

If turning off the heat sources to the cylinder solves the problem (try it a few nights), report back.
If it doesn’t solve the problem, report back.

Hi - ok so did some tests and pressure upstairs as measured on guage goes beyond static 2.5 to 3.5-4 when the hot water tank is being heated by gas.

When I then draw hot water from tap get the horrible noise and it seems to be coming from the EV side.

 

[Ben-gee]

I find it a bit difficult to see but is the expansion vessel teed off from the hot outlet from the cylinder?

 

[monkeydust]

Providing photo hopefully this helps