Vaillant Ecotec Plus 831 losing pressure overnight

[TBServices]

I believe it was installed in 2007/2008. We've been here 6 months and haven't had any problems until few days ago. What does b. mean? Would you mind elaborating?

Can't elaborate too much in case you try to do a DIY fix and blow yourself up.

 

[Boiler]

Can't elaborate too much in case you try to do a DIY fix and blow yourself up.

I must admit, I'm a keen DIY'er and will try my hand at most things but anything gas related is where I draw the line.

 

[Boiler]

Is there a way of "isolating" the boiler from the rest of the system to see if it still drops in pressure? I mean without fiddling with the internals or disconnecting pipes etc

 

[rawr]

there is

 

[Boiler]

there is

But are you also worried I may blow myself up?

 

[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