Central Heating Leaks

[fcc]

Does anyone have knowledge of Miracle Seal,how long will it seal a leak,how much do you need for a central heating system with 6 radiators in the circuit,thank you in advance for any information.

[gness]

fcc...before I waffle is this a pipe leak under the flooring?

[fcc]

yes it's under the floorboards,and there is no trapdoors to give access
to seek the leakout.

[gness]

Okay. In 2011 I moved house and had the boiler replaced. Immediately the pressure kept dropping. I was told it was a leak somewhere under the concrete floor and the floors would have to be dug up to find the leak at great expense. I'm an elderly lady suspicious of being taken for a ride.
I remembered Radweld from years ago so I asked if there was something similar....and did a little research. I was, reluctantly, told there was something similar that could be used.
I opted for that. It worked brilliantly and when I sold last year the CH was still working perfectly.
I don't know if it was Miracle Seal that was used but they're probably much of a muchness and I'd certainly give it a go.
Hope this is of help.

[douglas9401]

^Exactly what she said^ :-)

[fcc]

Thank you so much for your advice, i will go with that.

[gness]

Welcome. I was told that if the problem occurred again I could only use this solution one more time. At my age I’d settle for that. :-).
Hope it works for you too.

[Buenchico]

The Amazon reviews look quite promising. (Yes, I know that fake good reviews can appear online but it's much harder to suppress bad ones, and there don't seem to be many of them):
Amazon.co.uk User Recommendation

The advertising guff describes it as a permanent repair:

[Buenchico]

The manufacturer's data sheet states that 1 can is sufficient for 25 litres of coolant:
https://www.ct1.com/wp-content/uploads/bsk-pdf-manager/2016/11/miracle-seal-tech-data-sheet-industrial-05-04-2013.pdf

A post on this thread suggests that there might be 70 to 100 litres of water in your system:
https://www.diynot.com/diy/threads/calculating-water-capacity-of-heating-system.383994/

[alavahalf]

How do you know the leak is under the floorboards ?.. it's not the end of the earth to cut a hole in floorboards and use it to gain access. It is a fairly easy job for someone capable to cut out a section between joists, then fit a frame around the hole and re-instate the boards
If it was a last resort and you were I attempting to seal a central heating system I would use a tried and tested product that has been around for years ..

https://www.screwfix.com/p/sentinel-internal-leak-sealer-1ltr/99730?tc=XA7&ds_kid=92700055281954502&ds_rl=1249404&gclsrc=ds&gclsrc=ds

[gness]

Alav...I knew my leak had to be under the floor because it wasn't anywhere else....despite me walking around the house with my divining rods.

Out of curiosity, how would you decide where to cut the floorboards? I had concrete floors but either way it would have meant taking up all the downstairs carpets and underlay.