Megaflo Loud Vibration When Drawing Hot Water

[steveoelliott]

Hi,

I have an issue and it is somewhat intermittent whereby when hot water is drawn from my UV Megaflo, it makes a very loud vibration. The pipes can be seen moving slightly when this happens if you zoom on the video.

The external EV has been checked and it's set to 3 bar. Previously it was 1 bar but it made no difference to the noise. This cylinder does have the internal bubble but this has started to break down and hence the external EV.

The inlet valve and pressure reducing valve have been replaced already and the issue persists. I am confident the external EV plays no part in this. When this video was taken a significant amount of hot water had been used since the last heating cycle and testament to this fact is the EV was cold to the touch as was the pipe between that and the cylinder.

I am leaning towards thinking either a dodgy Non return valve (single check on top of cylinder) or something within the cylinder. Any feedback welcomed. I've decided the next course of action is the NRV. Interestingly, if you watch the video zoomed in you can see the tundish and pipe around it vibrate with the noise. I am even curious if this could be the pressure relief valve, but I can't think of any reason why it would do this. No water residue in tundish.

Thanks in advance.

 

[Johntheo5]

Did you recharge the air bubble since the noise started even though you have a external EV?.

 

[Madrab]

You need to see where the noise it being generated, that actually sounds like the noise the spring in the Pressure Reducing Valve (PRV) makes, rather than an EV noise.

Hold the combination valve and try to re-create it, it will be pretty obvious if it's the PRV. I know you've replaced the PRV but humour me

 

[Johntheo5]

You need to see where the noise it being generated, that actually sounds like the noise the spring in the Pressure Reducing Valve (PRV) makes, rather than an EV noise.

Hold the combination valve and try to re-create it, it will be pretty obvious if it's the PRV. I know you've replaced the PRV but humour me

Surely not!, wasn't this the one that replaced the "wrong" caleffi combination set?.

 

[steveoelliott]

Did you recharge the air bubble since the noise started even though you have a external EV?.

Yes this was completed even though it's non existent.

You need to see where the noise it being generated, that actually sounds like the noise the spring in the Pressure Reducing Valve (PRV) makes, rather than an EV noise.

Hold the combination valve and try to re-create it, it will be pretty obvious if it's the PRV. I know you've replaced the PRV but humour me

It is my intention to try and feel what might be causing this when reproducing it. However, it doesn't happen every time. It is sporadic. The previous Caleffe block was replaced due to this and a genuine Baxi part was fitted but the issue persists.

 

[steveoelliott]

Surely not!, wasn't this the one that replaced the "wrong" caleffi combination set?.

Yes it was.

 

[Johntheo5]

What about getting a PG installed somewhere and become the first in history to install a pressure gauge on a unvented cylinder?.

 

[steveoelliott]

What about getting a PG installed somewhere and become the first in history to install a pressure gauge on a unvented cylinder?.

I have had this suggestion previously... Where exactly would you install a PG or multiple PG's? To me it's another point that could leak but I see the fault finding benefit.

 

[Johntheo5]

I have had this suggestion previously... Where exactly would you install a PG or multiple PG's? To me it's another point that could leak but I see the fault finding benefit.

On a T piece with a isolating lever valve, just before where the EV is (copper?) piped into the cold feed.