Remeha Avanta combi boiler losing pressure.

[Barney1954]

Hi Terry, the heating was off at 10pm and I waited until 11.30pm before I turned off the isolation valves and switched off the electric. I will try the same tonight with balloons over the PRV and condensation pipe and see what happens in the morning. I guess the water must be dripping from one of these two places as I've taken a leaking radiator out of the equation.

Although, I'm competent at DIY, I did not feel confident enough to try the other suggestion. I'm retired and I know my capabilities by now! The new PRV was only fitted last Tuesday, but like any mechanical device they can fail, although I've not noticed any drips from it.

I was concerned the heat exchanger might have a leak, which I understand is very expensive to repair/replace. Although the boiler is only 6 years old, I'm thinking, for peace of mind, maybe it would be better to replace it with a Worcester Bosch boiler.

 

[terryplumb]

Hi. Best to establish for certain whats amiss before deciding a way forward. Yes heat ex is expensive to replace ,but boiler swap even more so, and winter is the most expensive time to have either done. It's a difficult judgement call ,repair or renew. If the boiler was ten years old you wouldnt be wise repairing. But six years old may well get another good few years if repaired. Who knows.

 

[Barney1954]

Good morning - As suggested I tied small plastic bags to the PRV and condensate pipe overnight. The PRV bag was empty and a small amount of water was in the condensate pipe, about a tablespoon.
Also this morning, my wife said the water was very hot from the tap, I had look at the pressure gauge, which was showing 2.6/2.7 bar (I notice you mentioned this in your first post).

 

[terryplumb]

I assume you isolated the electrics and boiler flow and return as well as tying bags. What was the pressure drop ?
Did wife run hot tap whilst boilet flow and return were still isolated ?

 

[Barney1954]

Hi - The pressure drop was similar to the previous day i.e. 1.5 to 1.2 bar, and I isolated the electrics and flow and return as before. After checking for water in the bags, I put the CH back on and it was about half an hour later that my wife ran the hot water tap.

 

[terryplumb]

At the moment you opened the isolators did the pressure drop any further ? The rise to 2.6 /2.7 bar when the c/heating was put on ( which you may never have noticed in the past ,possibly ) is indicative of a problem with the Ev. May just need to be re pressurised .

 

[Barney1954]

Hi Terry- I did not look to see if the pressure dropped when I opened the isolators, I could have another go tonight and check tomorrow. My wife confirms that the water was unusually hot today. I've had to put a little more pressure in the ev every week recently, is this likely to be the problem?

 

[terryplumb]

Well if you have been re pressurising the EV every week i doubt you have been doing it properly ,and that puts things in a different light. Are you just putting a pump on to it and pumping up ,without doing anything else ??

 

[Barney1954]

Hi - I first connected the pump about 3 weeks ago to check the pressure after keep seeing the F9 code, to hopefully cure the problem. I checked again after a week and put a small amount of air in. I changed the PRV last Tuesday and once again topped in up slightly.

 

[terryplumb]

But i am asking besides connecting a pump and pumping ,what are the other things that you MUST do when charging the EV ? Because i am not sure you are doing them !!

 

[Barney1954]

Hi Terry - besides when I changed the PRV, the other couple of times it was only really just to check the pressure, I take it there is something else I should be doing?

 

[terryplumb]

Yes .de pressurise and allow the drain point open to vent. So for an example ,go to a drain cock on a low point in the central heating system connect a hose to the drain cock , to outside drain. Drain water out and leave the drain cock open whilst attaching the pump ( with its own pressure gauge ) and pump up the ev to 1 bar. ( There are other ways to do it but this will do )
So you have de pressured the system.
You are using an independant gauge.
You are not pumping against system pressure.
And any water in the ev will be pumped out easily as the drain cocks open.

Your system will not function as it should if the EV is not charged correctly or if its defective and wont hold charge.

 

[Barney1954]

Hi Terry - once again, thanks for all your help, obviously I've a lot to learn! Do you think my problem is now more likely due to a defective EV rather than the heat exchanger?

 

[terryplumb]

First things first Barney , set the EV pressure in the correct way ,then see how things go. A lot of my earlier posts were made before i knew that as well as losing pressure and topping up system pressure you have also been adding pressure ,incorrectly to the EV.
Time will tell if the EV is kaput ,or if you continue to lose pressure.
By the way ,why did you fit a new PRV ?

 

[Barney1954]

Hi Terry - if I continue to lose pressure would this point to a defective EV? I changed the PRV because it was continually dripping and I hoped that would cure the problem of the F9 default. I read on one of these sites that I should also check the pressure of the EV so I checked the pressure using the foot pump gauge and topped it up very slightly each time. Just to double check, when I refill the system, do I do this via the filling loop? Sorry for so many questions, I wonder how you find time to answer all these!