Newly installed combi losing pressure

[hedylaura]

We just spent £3k+ upgrading our old open-vented system boiler system to a new combi condenser boiler (Viessmann 30kw) system which worked less than a week before the pressure dropped to 0 resulting in no hot water or heating. The plumber came and topped up the system saying it was "just one of those things" that happens occasionally for no discernable reason. So I duly paid him for his work. Then a few days later it happened again.

Now the plumber is saying ("in his opinion") that we have a leak in the pipework on the ground floor. He reasoned this because one of the radiators on the top (first) floor had completey drained, and had it been a leak on the top floor there would be signs of it on the ceiling. He topped it up again as a temporary measure so we were able to have hot showers on our return from a trip to Oz, but by the time we got back (less that 24hrs later) it had dropped to zero again.

He is suggesting re-piping the entire ground floor, which will ruin our flooring.

I can't see any evidence of a leak, and we had the place checked for damp not so long ago and this did not flag up any problems in the areas where we have pipework.

So my questions are - is he right? And are there any other ways to determine if/where there is a leak without going to the extreme lengths of ripping up flooring? Is it possible that the plumber caused the leak by over-pressurising the system?

And more importantly - am I liable for the additional costs that this will incur? In my view he hasn't finished the job he set out to do - we did not just buy a boiler off him, we bought hot water and heating. Both of which have been supplied for no more that a week in total since the installation 1 month ago.

Thanks for your help!

Hedy

 

[GrahamM]

Was it just a boiler upgrade using the original radiators and pipework?

 

[rodders]

was

Is it possible that the plumber caused the leak by over-pressurising the system?

It is always a concern when changing from open vented to a sealed system that the old pipework may not be up to the pressure required for a sealed system. This is something I would have pointed out if I was the plumber. The PRV should kick in at 3 bar so it couldn't have gone over 3 bar so I would say he has not caused a leak by over pressurising but the old copper was not up to the job.

There could be another issue so I will ask this. What was the pressure when you topped it up when cold?

 

[hedylaura]

Yes it was.

 

[hedylaura]

was

It is always a concern when changing from open vented to a sealed system that the old pipework may not be up to the pressure required for a sealed system. This is something I would have pointed out if I was the plumber. The PRV should kick in at 3 bar so it couldn't have gone over 3 bar so I would say he has not caused a leak by over pressurising but the old copper was not up to the job.

There could be another issue so I will ask this. What was the pressure when you topped it up when cold?

Not sure, I haven't been there the times he has topped it up.

 

[hedylaura]

Just spoke to him on the phone. I asked if there any way of testing the system before committing to ripping up the floor, and he said no, unless we wanted to isolate the downstairs pipework from the system and wait for a week to see if there was any pressure loss. This doesn't seem like too bad a prospect, we can hole up upstairs for a few days and at least we'll have hot water, but he was clearly trying to talk me out of it.

It also took a while to hammer him down on how much it would cost. He eventually said around £400. I expressed my discontent at having to pay for this when in my view, this should come under part of his quote which says (and I quote) "Re-pipe to accomodate new position or system type" as the old pipes clearly do NOT accommodate the new system type.

To be fair to him though, NONE of the other plumbers we got quotes from ever highlighted a potential problem with switching to a sealed system with old pipework. Wishing we just got a new cylinder now because the old boiler was fine...

 

[GQuigley67]

my contract clearly states i wont be held responsible for leaks caused by increases in pressure on existing system, and it should not be his fault either, its one of these things which happens unfortunately, not all the time, but sometimes. How big a leak ? how long does it take to loose pressure ? adding leak sealer to the system may help

 

[rodders]

Not sure, I haven't been there the times he has topped it up.

The system should be around 1 bar when cold. Read the boiler manufacturers instructions for their recommendation. I state this as if you say it doesn't look like a leak I would eliminate the possibility that theres too much pressure in the system to start with. If its filled to 2 bar for example as the water is heated the pressure increases and the pressure relief valve may open making the system lose pressure. Check this first (pressure when cold 1 bar).

As someone just said leak sealer may be a good option if the pressures are confirmed to be correct.

 

[hedylaura]

my contract clearly states i wont be held responsible for leaks caused by increases in pressure on existing system, and it should not be his fault either, its one of these things which happens unfortunately, not all the time, but sometimes. How big a leak ? how long does it take to loose pressure ? adding leak sealer to the system may help

Less than 24hrs. He said that he did not recommend using leak sealer with a brand new boiler. Do you know why this is? I was not shown any kind of contract before the work was carried out. If I'd known this and the potential risks I would have thought again. Plumbers hold all the knowledge and therefore have a duty to the customer to let them know all the risks and what they are/are not liable for.

 

[GQuigley67]

I have never had to use leak sealer on a new boiler so will have to look into that one myself, but when changing from an open vented system which has a pressure of 0.1-0.3 bar roughly, to a sealed system which will have a pressure of 2bar(+/-) when hot, then there is a good chance of leaks on the existing pipework, this must be made clear as if it does happen customer will blame the installer. I explain this and have it in my terms and conditions so once customer signs it I am no longer liable.