HELP!!! Vaillant Eco Tec Plus System Boiler

[chas629327]

Hi Guys

Im new here and hoping to get some much needed advice.
Had new boiler as above fitted about a month ago. Everything was fine then last week noticed pressure was down to almost zero and boiler wouldnt fire. Filled up system and was ok. For about a day. Today has been the worst and it has had to be topped up 3 times. Looked everywhere for leaks and found nothing. Not just a quick check but every TRV, lockshield, vents etc and all visable pipes. This evening have even gone as far as cutting up some brand new oak flooring on ground floor to no avail. Obviously checked overflow pipe etc, - all the obvious things and nuffink! Its driving me mad

After googling the only thing i can see is that theres more chance noticing leaks when system is cold - makes sense - but is there anything else anyone can advise before i go completely mental

thanks

 

[buffy27]

well , whats the craic.
not to familiar with the exact set up{not to popular here in ireland} but maybe domestic and heating waters are mixing{any discolouration in domestic?}
can u see if all safety valves are operating properly{sometimes they maybe tied in to wastes etc and are not visible{u don t know if they are releasing water or not }


otherwise if the heating is zoned u could find which zone it is loosing it on, by closing off individual zones.this won t sort u ,but it will b a step in the right direction.
maybe then an air compressor could b hooked up to a waterless system.try then goin around to places where there are fixings in the floor and with suddy water u may get air bubbling up.there s every chance u may hear the air also.
the last resort would b a thermal imaging camera, if u know anyone has one. let me know how u get on , buffy

 

[Mike Jackson]

If there are no visible leaks it could be a hole in the coil in the cylinder. Was the original cylinder kept when the boiler was swapped?

A way of investigating is to leave the filling loop turned on slightly so that the pressure remains constant and listen to the pipework. You should may hear a hissing near the leak. If your cylinder is cistern fed make sure no one uses any water and check the level in the cistern, if it rises the coil is faulty. If it's an unvented ignore this as the water would flow the other way with a faulty coil.

Mike

 

[chas629327]

Thanks for response so far. It was a whole new installation i.e all the plumbing in the house. Im going back soon to check that its nothing stupid like a toilet cistern connected to heating circuit etc (like you mentioned - central heat / hot water mix up)

It is zoned so the next step will be to cap off the zones one by one and see if I can determine which is the problem.

I was excited by the idea that it might be a hole in the coil in cylinder - but yes it is unvented so does that definitely rule that scenario out?

Air compressor is interesting. Anyone got any ideas as to what kind of compressor and how exactly?

Im also about to phone the thermal imaging people for a quote - as a last resort

In the interim thank you anyway guys

 

[stevetheplumber]

you could try putting the preasure up tp three bar with the boiler of and rechecking everything sometimes the extra preasure will show the leak after that its a xas of isolating circuits and preasure testing seperatelywith either air or water at higher preasure using a guage and leaving each circuit for an hour see what drops

 

[buffy27]

well whats the craic.
have u really checked everything.
did u sus out the safety valves.
a small air compressor , something to give u a few bar.u use a test piece and tie it into system.
have u contacted the plumber yet.i m sure he ll b keen to rectify this. i know it would really anoy me if i left someones house like that, buffy

 

[chas629327]

Hi again

Still no luck plumber was there with me all day with couple of other people as well _ its a big house)

We let the system go cold and it appears to lose pressure much faster when its cold

Re-filled loads of times and still no water stain in any of the ceilings. Assuming in must be on the ground floor under timber floating floor with pipes buried in screed.

Have had it up to 3bar on cold and just loses at the same rate with no visible signs. Tomorrows job is to cut the ground floor zone and refill system. If it all holds would indicate its definitely on the ground floor and then try pumping dry circuit with air and listening for a hissing sound. Im also inclined if that fails to find problem to just leave the filling loop slightly open with boiler running and eventually i presume ill see some water damage downstairs? Is that such a bad idea?

Leakbusters - a company in london can come with thermal imaging camera (£400+) and if that fails to see the problem can apparently drain system and pump gas into it then sniff mechanically for the leak (another £200+) , but still tomorrows another day and will try to pinpoint the problem by isolating zones.

Im so stressed!!!

Thanks for your input guys - its appreciated (and keep it coming!!)

 

[Deleted member 2053]

Yes it could still be the coil in the HWC with a sealed system. Personally I think I would be tempted to put some dye in the system and see if that revealed anything.

 

[chas629327]

To previous post

any ideas of where to get dye and what type etc. Also is there any other way to ascertain if that is the problem. What i mean is any method besides dye?

If i were to cap of flow and return to cylinder and just filled the central heating side - and the pressure remained constant that would show that there was a coil problem?

dyou think?

 

[stevetheplumber]

drain the cylinder ,leave the drain of open ,fill heating and see if it starts to run out of the drain of which it will if the coils gone