Potterton Combi 80 nightmare

[corgiman]

If the leak was in the combustion cahmber it would have definately shown itself by now I would say

 

[bones001]

yes but if the boiler is on all the time the heat would poossibly dry it out, just guessing as its better to check everywhere before ripping floors up

 

[corgiman]

Witht he ammount of water that is lost in a day (its being topped up twice) dont think that it would evapourate that quickly, and the gromits would leak even with a smidgeon of water there, so still dont think its worth a look, but hey you never know, many a times I have been taken by surprise, no dinner, pictures nuffin just taken by surprise

 

[ChrisR]

Does the pressure go down while the boiler's off? If you aren't sure you could turn off its isolation valves and leave it overnight. If (as is usual) they leak through the gland seals you'd need to renew them, so do it first. Not expensive compared to digging up floors.

 

[S&LBaillie]

Hi all

thanks for all your replies. Were working through them all one at a time!

Ripping up the floor is going to be our last option as there's hell of a lot of concrete floor!

When the heating's running the floor does get warm in the lounge as the pipes are quite close to the surface. this hasn't changed and we did dig around that area just in case the leak was there (it happened 3 yrs ago in the same spot) but nothing.

We refilled the system this morn as i explained to 1.5 bar and have had the heating on once plus managed 2 showers and it was ok. then we went out and came back 4 hrs later (heating off during that time) and pressure nearly on the red.

There isnt any water leaking from inside the boiler itself and when we re-fill it runs fine while the heating is on and manages to hold the pressure better.

It's obviously something thats happening while its off.

typical i can see us knocking the lounge to pieces! although i have parents in fire brigade so will try and sort out a thermal imaging thing!

 

[EliteHeat]

Have you tried putting some leak sealant into the system?

 

[S&LBaillie]

Hi

No we haven't tried that yet, but will give it a go. Is there anything in particular we should look out for when buying leak sealant?

also we have kept the bag over the PRV out pipe which goes outside and it has a small bit of water in it when checked today (by small i mean about a teaspoonful). Could this be anything.

thanks

 

[HarrogateGas]

Leak sealer will not work if the leak is a s large as your where you are topping the pressure up daily. It will not work so save your money!

 

[corgiman]

Agree with harrowagte, leak sealer only works well on seeps

 

[S&LBaillie]

Ok thanks guys, wont bother with that then.

Any ideas on the water in our bag that we attached to the pipe? is that enough to be losing pressure or should we be expecting gallons of it coming out!

 

[meldrew's_mate]

Have you had a look in the combustion chamber on the boilr, the heat exchanger could have a crack in it and leaking from there.

Presumably the CORGI would have noticed the leak inside the boiler.

As has been said, and we still keep coming back to, it's probably a leak under the floor. A decent fitter should be able to isolate downstairs and use a water pressure tester to quickly identify if there is a leak there. If so, pressurising to 3 bar with air will enable you to listen for the hiss of escaping air/water and home-in on the leaky area. Then you dig. After several weeks of putting 2 to 3 pints in (and losing it) three times a day there may not be much concrete left in the leaky area

In the meantime run the upstairs and enjoy a pressure stable system

 

[S&LBaillie]

Thanks, will endeavour to get plumber bloke round again.

As you correctly said, there isnt a problem inside boiler so it must be the damn floor! will watch out for soggy concrete and holes!

Thanks

 

[S&LBaillie]

Hi,

Still unable to locate the leak in concrete and even pulled up the kitchen carpet today for a better look.

Just a thought but we haven't been able to run the DHW supply on its own since this problem started.

If the CH is set to off and the pressure is low we cant run the hot tap for long as the boiler starts hissing and spitting.

Could this indicate that Heat Exchanger is up the shoot and the CH water is crossing over into the DHW supply?

Or are we completely barking up the wrong tree?