Vaillant Ecotec Plus 831 losing pressure overnight

[Boiler]

Hi all,

I'm having problems with my boiler and am hoping someone can offer me advice. Few days ago our heating and hot water stopped and on inspecting the boiler I was met with the F.75 error. We had a plumber come out and the first thing he asked was if I had the owners manual which didn't fill me with confidence. Anyway, I didn't have one as we recently moved in so the plumber tried refilling the system to bring it up to 1.4/1.5 as he said this what Vaillant's were supposed to be at. It got it working which was great until yesterday morning when we lost heating and hot water again. As I had watched what he had done, I refilled it and again this morning the pressure had dropped.

Now before I call a plumber out again, I want to try and narrow the issue. I have been searching and found that it could be a number of things but I want to try and establish if it's a leak in the system or if it's a problem with the boiler. Is it possible for a DIY'er to do this? I have checked the visible areas around the radiators for a leak but can't see any signs of one (assuming that going from 1.5 to 0.9 in less than 24 hours would mean a reasonable size leak!). Also, there are a few "valves" with screw slots underneath and one was at 45 degrees. Should all the valves be closed? If not, which ones should be open and which should be closed?

Any help/advice appreciated.

Thanks.

 

[rawr]

haha I know you won't, but you might

 

[Ian400]

Try this site to download vaillant manuals, [DLMURL="http://www.vaillantdownloadservice.co.uk/Pages/Default.aspx"]Vaillant Technical Download Service[/DLMURL]
Find the Isolating Valves on the Flow and Return pipes under the boiler, turn them Off, and leave overnight to see if it makes any difference to pressure loss. ( don't use the central heating during this time ).
You can check the PRV ( Pressure Relief Valve ) is letting by, by looking for the pipe which goes from the boiler through to the outside.

 

[novicegas]

Use the right size Allen key to turn the flow and return isolation valves off or you'll find you rip and damage them using a slotty. Prv can be easily checked. A vaillant savvy engineer will be able to cycle back through the faults on a three year old v combi, might be able to detect some other previous fault that might shed some light on this one. Any pipes on ground floor that might be letting by, under screed or floor boards, fernox leak sealer will only deal with small weeps not drops of your like.

 

[lame plumber]

if you say that the boiler runs ok when pressurised but loses pressure overnight, probably what's happening is the expn vessel has failed and this means when the boiler runs, there's nowhere for the hw to expand and the prv operates until 3 bar is established, then everything is tickety until the heating goes off, water cools, pressure drops and next morning boiler wont work due to low system pressure. So ask engineer to check expn vessel first before looking at prv and other leak possibilities.

from memory doesn't gsr state you shouldn't work on a gas appliance without access to the mfis

 

[stevetheplumber]

we are not actually supposed to work on any appliance with out the manufacturers instructions present a lot of engineers will have a laptop with them onyears ago we had a plate on the boiler which told us everything we needed to know now the plate would need to be as big as the boiler

 

[Centralheatking]

I advise u get a vaillant listed engineer in - mucking about with pressurised systems when you
have little knowledge is v. dangerous. Combi systems and other pressurised set ups have highly
pressurised v. hot water all around the circuit. Get it wrong and if you unlucky someone dear to you
can get scalded - last one i read about was a baby in bed - pipe above over pressurised - 2-3 degree burns.

centralheatking

 

[Boiler]

Well... the boiler is screwed. Had a leak which wet pretty much the whole of the inside. It's water tight now but still getting errors and I think due to water getting everywhere it may be beyond economical repair.

So my question is, what is a reasonable price for a new Ecotec Plus 831 and like for like replacement fitting? I'm also thinking about getting a Magnaclean and some sort of limescale filter fitted at the same time. Probably need a power flush too.

Im in NW London and for the boiler plus fitting have been quoted £1600 (excluding the extras). Is this reasonable?

 

[tom609]

cheap price, check your house insurance some policys cover this, worth a phone call

 

[Centralheatking]

£1600 in London seems pretty good to me - but just what is the quote for ? - post it on here and we can all go over it - have you tried an independant Vaillant specialist - they can work wonders -
magnaclean is only one ferric sludge capture device there are others - which are better in my opinion and can do more - pm me if you want more totally independant info cause the centralheatkings do not do N London - we stick to West Lancashire

Well... the boiler is screwed. Had a leak which wet pretty much the whole of the inside. It's water tight now but still getting errors and I think due to water getting everywhere it may be beyond economical repair.

So my question is, what is a reasonable price for a new Ecotec Plus 831 and like for like replacement fitting? I'm also thinking about getting a Magnaclean and some sort of limescale filter fitted at the same time. Probably need a power flush too.

Im in NW London and for the boiler plus fitting have been quoted £1600 (excluding the extras). Is this reasonable?

 

[tom609]

this is an old post sure its sorted by now

 

[Roger Welton]

Op posted again today.

May be worth a go at getting Vaillant out on a fixed price repair?

 

[Destroyer2813]

Sure be worth a try i had Baxi heateam out on a 7 year old solo pretty much rebiult the whole thing after the hex leaked , will be much cheaper than a new one if they will do it

 

[tom609]

4weeks old is the thread merry christmas to all

 

[Destroyer2813]

Yeah the thread may be 4 weeks old but READ what Roger wrote the op posted again about it Today

 

[dancinplumba]

toms on the pop lolol