Leak sealers and inhibitors

[B91]

This is a large house with old iron CH pipework. Minimising leaks and corrosion is expensive - typically we add three F1 and three F4 bottles after a draindown and refill so we have to try to avoid this as far as possible. Last week the automatic air valve on the Vaillant 835 failed and the system lost a lot of water overnight so now I'm wondering what effect the refilling may have had on the F1 and F4 concentration levels. I could ask my plumber but tbh I don't feel I would be able to trust his answer. Seems to me that it depends on whether these additives are held in suspension or are dissolved. If they are in suspension it could be there's no need to add any more, but would definitely need to top up if they are in solution.

The plumber has suggested Miracle Seal as an alternative to Fernox F4. He is coming Wednesday March 22 - any answers/suggestions before then would be really appreciated.

 

[ianmcd]

I wouldnt use any leak sealer and certainly wouldnt mix them , find the leak and sort it

 

[B91]

Easier said than done as it's somewhere under a 6" concrete raft about 50' x 25'. F4 has kept it well under control for more than 10 years, by which I mean losses in this big system are minimal, about 500-600ml (a pint) a month. I think I agree with you about not mixing them though.

 

[ianmcd]

you will read so many posts on here about how dirty water causes problems with boilers, adding leak sealer is making the water in your system like mud to seal small leaks , boilers hate it and some boiler manufacturers will not honor warranty if leak sealer is added, mixing different types could seriously damage your system or boiler , they might react with each other and completely block up either a pipe or inside your boiler

 

[B91]

Well I don't have the luxury of choice, and as F4 has not caused any problems over many years I can only keep my fingers crossed.

 

[dilalio]

Well, it's just an Elastoplast on a broken bone then! Do what you have to do.

 

[oilboffin]

If you feel you can't ask your plumber cos you don't trust his answer dont you think it's time you got a plumber you can trust.Bob