Remeha Avanta combi boiler losing pressure.

[Barney1954]

Every morning over the last month, I've had the F9 error code and added water through the filing loop. I've now replaced the pressure relief valve and topped up the expansion vessel to 1.0 bar on the boiler, which appeared to have fixed the problem. However after 4 days, once again I've had to add more water through the filing loop.
Does the expansion vessel need replacing or might this be a leak in the heat exchanger?

 

[terryplumb]

Does boiler pressure get upto or close to 3 bar when c/heatings on ? If so the EV needs attention .

 

[Barney1954]

No, the pressure is just over 2 bar when running.

 

[terryplumb]

And the PRV is not letting water out now ? Next thing to establish would be to find out if water is lost in boiler or in the system

 

[Barney1954]

There does not appear to be any leaks from the first floor radiators, I've hard floors laid on the ground floor, so not so easy to check for leaks. How would I check to see if water is lost in the boiler?

 

[terryplumb]

Tonight turn heating off an hour earlier than usual to allow all to cool down. Ensure pressure is 1.5 bar after system has cooled. Electrically isolate the boiler ,and isolate the flow and return pipes at the boiler. Leave overnight. In the morning if pressure has dropped then water is being lost from the boiler. If pressure has not dropped ,open both isolators and if pressure then drops ,water loss is external.

 

[Barney1954]

Thanks Terry, I will try that tonight.

 

[Barney1954]

I've been checking the PRV during the day and it does not appear to be leaking. I've had another look at the boiler and the isolating valves, does it need a quarter turn on the square slotted screw to turn the valves off?

I forgot to mention that I've also been checking the amount of water dripping from the condensation pipe, which is around 2 litres a day, is this normal?

 

[terryplumb]

Condensate should not be coming from the boiler whilst its not being used at all. The iso valves are 1/4 turn usually.

 

[Barney1954]

Thanks again Terry, the water is only dripping whist the boiler is running. I only checked how much water was dripping out of the pipe because of the problem above, I've never looked at this before, I assume a couple of litres is normal for a combi-boiler.

 

[terryplumb]

Pretty much, It does vary though. However if water comes out the condensate pipework continually when boiler is not in use ,thats a sign of trouble ,and pressure would be lost.

 

[Barney1954]

Good morning, the pressure dropped from 1.5 to 1.1 bar overnight, I guess water is being lost through the boiler.

 

[dilalio]

Good morning, the pressure dropped from 1.5 to 1.1 bar overnight, I guess water is being lost through the boiler.

Have you checked the air side pressure of the EV? This needs to be done and pumped up whilst the water side is depressurised. You need to open a drain cock (on boiler or system NOT PRV) and allow water to pulse out whilst you inflate the EV. If this is depleted and has activated the new PRV, you "might" need a new one of those again as they are prone to failure once activated!

 

[Barney1954]

Hi - I might be outside my comfort zone on this as I'm unsure what is needed.....and I do not have a pump!

 

[terryplumb]

If your sure the system had cooled before you did the test. Its a fair chance that the heat ex has a leak . The test you did is not conclusive proof ,as it assumes that both isolators will 100 % seal. You can do the same test again ,and if the condensate pipe end can have a balloon put over ,same on prv to catch any water ,then you would pretty know for sure its boiler loss.