Leaking central heating - should I use an internal leak sealer?

[Shaun87]

I have an 18 month old central heating system with a combi boiler and pushfit pipework. Everything works OK but the system loses pressure after about 3 months. I can't find any obvious leaks or weeping joints. Would a leak sealer like fernox f4 be a good solution?

Thanks

 

[Rickster123]

No a good solution is to find out where the drop is coming from. Rad valves are most likely and the smallest of drips will drop the pressure over that time period.

 

[Shaun87]

No a good solution is to find out where the drop is coming from. Rad valves are most likely and the smallest of drips will drop the pressure over that time period.

I've checked all visible valves and have been unable to find any leak. I'm reluctant to pull up my laminate flooring for such a small leak. Should I let the leak continue? Is a 3 month drain out that bad?

 

[Old Account]

Most likely prv or expansion vessel or under the floor some joints ...

But I suggest to get a gsr - plumber in to solve the issue might be something wrong with the boiler

 

[plumben]

Check all radiator valves
Take the heads off trv valves and the white caps off the lockshileds if fitted and check for signs of water corrosion or rust
Same on the bleed valve end and blank end of the radiator

Check the blow off pipe on the boiler is dry or for signs of water

If you can't find anything then call the installer who fitted the system