Remeha Avanta boiler losing pressure - what to try next ?

[mjgreen81]

Hi all,

This is my first post to the forum but I have lurked for a while and would like to thank everyone for their helpful comments.

I have a Remeha Avanta condensing boiler that rapidly loses pressure and requires topping up every few days. I have checked the house all over for leaks and everything looks fine (this has been happening for a few months now so if there was a leak I would have (hopefully) found it by now.

The boiler seems to clunk away with the pressure gauge bouncing up and down until I top it up from the filling loop.

On the outside wall I can see that there is regularly a lot of water around the overflow pipe, so it looks like this is where it is going.

So far I have replaced the pressure gauge as when I first discovered this problem the pressure gauge appeared to be stuck at about 0.5 bar which caused some confusion. I then read that it was fairly common for these to get dirt in and fail. This is now working but does not seem to have helped the initial problem, so looks like a totally separate problem.

I have also recharged the expansion vessel as this had no air in it.

Each time I fixed something I hoped it would resolve the problem, but no luck!

Will the next thing to try be the pressure relief valve? Or is there anything else I should try first?

I am not sure if it makes a difference, but I have only been using hot water over the summer so I am not sure what will happen when I put the central heating on. I need to try and get this sorted before it starts getting cold!

Thanks all.

 

[mjgreen81]

As a little update, I did some experimenting this afternoon.

I noticed that if I deliberately overfill the boiler to 3-4 bar pressure, the system spits a load of water straight out of the overflow, and eventually settles at around 1.5 bar. As I understood it the PRV is supposed to release at 3 bar, so does this add to the likeliness of a failed PRV?

Two other things I noticed while deliberately over pressurising (which may or may not be significant), the first run of water out of the overflow was brown and dirty (like when you drain a radiator). I was surprised by this as the system has been releasing water from the overflow and I have been topping it up every few days for a while now.

I also noticed a small drip of water coming somewhere around the pressure vessel. Im not sure where it was coming from, but it was not the schrader valve. I havnt seen this leak before, it just seemed to occur because of the over pressure.

 

[ServiceNumpty]

Get someone in to check the exp vessel charge and probably replace the prv. I have replaced a couple of pinholed heat exchangers on these as well. But would need RGI to check this out.

 

[mjgreen81]

Thanks Michele.

As mentioned above I have already checked the expansion vessel and although it was empty, I recharged it and it seems to be holding the charge since, but the problem persists, so I guess PRV is the next thing.

 

[MickyP10]

Inclined to agree with above, new pressure vessel and release valve. You said it was leaking somewhere, didn't you?

* Not sure whether over pressurising the system is a sensible thing to do, as you had the problem at running pressure and it's likely to make the relief valve leak if it wasn't before. Not an expert, though, so see what they say.

 

[mjgreen81]

Hi Micky,

Thanks for the feedback.

It only seemed to leak when I upped the pressure to over 3bar (it has not leaked before that).

You are probably right about not over pressurising the system, but I just wanted to check what would happen when I went over the 3bar limit that the PRV is supposed to kick in at.

Hopefully i have not done any damage :/

No water is escaping from the schrader valve on the expansion vessel, so hopefully this is not a problem.

The fact it dropped down to approx 1.5bar I seemed a bit strange.