Central Heating Leak Sealer

[stevedo]

Has anyone used and had success with one of the central heating leak sealers? My sealed system has started to lose approx 0.5bar over a 4/5 day period. I can find no leaks. My concern is that the leak is on the downstairs level where all the pipework for the system is buried in the concrete floor. This concern is well founded as this would be the 2nd leak we have experienced in the < 1 year we have lived in the house. The first leak resulted in system pressure reducing to zero in about 2 hrs though and we had to remove the solid wood floor and dig up the concrete. This leak is much much smaller and would be almost impossible to locate if in the pipes in the concrete floor!

I was thinking of using the Fernox central heating leak sealer product.

Thanks
Steve

 

[Bahco]

Sorry , I don't know much about leak sealer but think its worth a try if you cannot find the leak.
To all those that advocate burying pipes in concrete ..... think again.
I have refused to do this on a couple of occasions as any leaks will be a nightmare to find and fix.

 

[kevplumb]

if the pipework is buried in comcrete and not wrapped the lot is liable to be rotten

 

[stevedo]

if the pipework is buried in comcrete and niy wrapped the lot is liable to be rotten

Hopefully not as the pipes seem to be mostly stainless??? Previous big leak was caused by a fitting that had completely fractured, not corroded.

 

[ChrisR]

Stainless is unlikely in a CH system. It would still corrode in cement. If you have Nickel (looking) plated steel pipe then gawd help you. Try with a magnet.
Look hard at pressure relief pipe for drips.
LS can work ok.

 

[stevedo]

It's definitely stainless, I've tried the magnet test. The house was built in 1971 and I'm told there was a copper shortage at that time and the builder used stainless instead.

 

[stevedo]

Stainless is unlikely in a CH system. It would still corrode in cement. If you have Nickel (looking) plated steel pipe then gawd help you. Try with a magnet.
Look hard at pressure relief pipe for drips.
LS can work ok.

Where would I find the pressure relief pipe? The boiler is a Worcester Bosch Greenstar 28HE if that helps.

 

[DarkInferno]

it is likely to be sticking outside underneath your flue, probably in copper and it should have at least one 90 degree elbow in it. Check it isn't dripping, it may also be an idea to monitor the pressure gauge whilst you heating is on... check it doesn't rise drastically.

Stainless will still corrode in cement, nasty stuff cement.

 

[stevedo]

it is likely to be sticking outside underneath your flue, probably in copper and it should have at least one 90 degree elbow in it. Check it isn't dripping,

I know the one you mean, I'll check it out.

it may also be an idea to monitor the pressure gauge whilst you heating is on... check it doesn't rise drastically.

It rises from about 1 bar cold to 2 bar hot. According to the gauge this is within operating range (as signified by the green shading)

 

[sennapod]

So, reading the above, does that mean that copper corrodes in concrete too ?
I've a similar problem - minor leak copper in floor screed (which I assume is concrete based). copper pipe is wrapped in hessian tubing. Then levelling compond and ceramic tiles on top.
Has been like that for 4 years - but now just started to leak.

 

[Bahco]

now just started to leak.

Enjoy the repair

 

[namsag]

Lots of houses done in stainless steel around the time your house was built if it`s starting to leak the sealer may work but what usually happens is once it starts to leak you will get loads of them and is far better to just bite the bullet and repipe the system.

 

[stevedo]

Lots of houses done in stainless steel around the time your house was built if it`s starting to leak the sealer may work but what usually happens is once it starts to leak you will get loads of them and is far better to just bite the bullet and repipe the system.

The bullet has been bitten. Bit of a long story but here goes.

Tried the leak sealer without success. Leak got progressively worse until the system was losing about 0.8 bar pressure in about 12 hours, maybe another fractured fitting. I was not comfortable with this level of leakage and turned off DHW and central heating, closed all rad valves to hold existing water in rads and used immersion to heat DHW.

At this stage a search started for a heating engineer/plumber who would be willing to take on a re-pipe. Given that we have about 75m2 of hardwood flooring downstairs in one continuous fitment I did not want this disturbed. I found someone willing to re-pipe by putting new pipes behind skirtings. This will entail pipe runs going upstairs and coming back down at appropriate points.

In the meantime, to give us heating upstairs and DHW, the whole of the downstairs has been isolated such that it has in effect been decommissioned. It will lay dormant in the concrete for ever I guess.

Plumber is due to start work on the 8th November and job will take about 3 weeks.

At least then I will be able to sleep without worrying about getting another leak in the floor.

Steve

 

[ricarbo]

I think you will find if you look on the pages put out by the copper development asociation on the net, that stainless steel pipe is not approved for use in concrete floors. they also give recommendations as to how you should do it - using copper.