Leak Sealant - effective and safe?

[nervous123]

I suspect we have a leak in our sealed unvented CH system - pressure seems to drop, albeit slowly. The situation improved drastically when a HE put Fernox inhibitor in - now pressure drops about 0.1 bar over 2 months.

Would Leak Sealant be sensible? I have heard Vaillant will not honour their warranty if leak sealant inserted into system // that it can block up the boiler...are either of these true? (My boiler is Vaillant Ecotec 630 plus - not combi)

Thanks a lot, as ever.

 

[Blackcatgas]

Ive always been sceptical and reluctant to use leak sealer, prefering to find the leak, however I tried some 6mnths ago on an old system as a last resort, the customer couldnt affors/didnt want the floor chopping up and was happy to try the leak sealer as a last resort.
It has worked a treat, and the boiler hasnt died of aids, the aavs still work etc etc.
On a side note your system could be full of sludge which is causing "gasing up" ((hydrogen gas produced when the metal radiators corrode internaly)), this then fills the rads with gas so you bleed them then have to put more water in, the inhibitor would have reduced this effect, does this make sense in your case?.

 

[Billy Bob Bob]

never used leak sealer,if you have a leak find it and fix it

 

[Puddle]

How would you find such a small leak ?

sometime deeds must

how many radiators do you have on the system nervous 1

 

[Billy Bob Bob]

Ive always been sceptical and reluctant to use leak sealer, prefering to find the leak, however I tried some 6mnths ago on an old system as a last resort, the customer couldnt affors/didnt want the floor chopping up and was happy to try the leak sealer as a last resort.
It has worked a treat, and the boiler hasnt died of aids, the aavs still work etc etc.
On a side note your system could be full of sludge which is causing "gasing up" ((hydrogen gas produced when the metal radiators corrode internaly)), this then fills the rads with gas so you bleed them then have to put more water in, the inhibitor would have reduced this effect, does this make sense in your case?.

well if it works,never used it so cant really say what damage it would do if any,but i see it a bit like k seal on a car yes you know the heads knackerd but this stuff may work but ultimately the problem may come back

 

[diamondgas]

I've found this stuff of limited use! However with such a small loss in pressure it could be of benefit!

By-the-way! You've probably done it already but check all your radiator valves .. Good way is to tie some loo roll around the pipes to and from your radiators... give it a night and you'll know if any are leaking or not!

 

[nervous123]

Thanks to all responses.

Blackcatgas, if they are full of sludge, how do I go about cleaning them? We had a Magnaclean filter installed, should I check that?

gasman, I am interested in leak sealer precisely because any leak, if it exists, will be really small and hard to find.

diamondgas, Some pipes do have green crusts/stains on them which I need to scrub off, then wait and check if the valves are leaking.

puddle, We have 12 rads - 5 are new and 7 are (very) old - I dont know what the state of the pipes are, contractor said he'd replace 'where necessary', i reckon he may have played it safe (or cheap) and kept a lot of the old ones.

 

[mfgs]

If the situation improved alot with inhibitor added, then that sounds like corrosion was causing gases to be formed and vented out of auto air vents and in doing that dropping the pressure. 0.1bar over 2 months is absoloutely nothing, I'd be tempted to add a little more inhibitor before leak sealer.

The only time I have used leak sealer is for a leak under solid concrete flooring and it worked a treat.

 

[villa_tom]

To be honest a 0.1bar drop over two months wouldn't bother me, you'd only lose just over half a bar in one year and most sealed systems that I service need a little top up when I'm there. As long as your heat and hot water work well I would just leave it, but thats just me!

 

[aggis]

Agree with Villa-tom, 0.1 over 2 months is nothing, but if there is crusts around nuts/valves, that could be the problem, unless you really know what you're doing leave it to an expert.