HeatraeSadia Electromax vibrations after service: Is this an EV pressure issue?

[IainT]

Our HeatraeSadia Electromax boiler has just been serviced. Since the service we get a lot of vibration from the system each time the hot water is run after the system has been heated up. After some investigation and correspondence with the service engineer we concluded that it was probably
because the charge pressure in the expansion vessel was higher than the dynamic pressure of the cold water supply, which can lead to a short period of vibration as system pressures equalise when hot water is drawn off. He came back to lower the pressure in the EV ( taking 0.5 bar of it ) and he measured the supply pressure ( which he said was reasonable, but I don't have the actually measurement ). Since then the vibration has been better but it is still there. Do you think we are on the correct path to fix the issue, or is there something else that could be causing this problem. The service engineer tried to convince me that by bringing the EV pressure back to the correct level in the service it might have uncovered another issue ( which would need further investigation and by implication more cost ). Any advice gratefully received.

 

[EvilDrPorkChop]

Possibly could be non return valve chattering in combination valve. Without hearing it hard to say, you need to get your G3 engineer back to investigate further.

 

[IainT]

Possibly could be non return valve chattering in combination valve. Without hearing it hard to say, you need to get your G3 engineer back to investigate further.

Thanks for your reply. The problem with bringing the same G3 engineer back is that they will only re-visit on a new call out charge (even though the issue appeared after the service) and realistically they would need to hear the noise, which only happens when the water system has been heating up over-night. So I could end up paying again, and the engineer might still not be able to pin-point the issue. We have only been in this house a couple of years and on each time the system has been serviced ( only twice ) the EV has been liquid full. I'm wondering if there is any connection here. Is it normal for the EV to need emptying and re-pressuring each year?