Fernox leak sealer and similar.

jobloggs · 22 Mar 2006

Any of the experts on here have any experience of this type of thing?

Do they work at all? (I realise a plumber would not stake their reputation on them and would prefer to replace radiator, pipe or whatever)

If so do they only work if pinhole is leaking to air outside or would they work for a pinhole in a cylinder coil with water inside and out?

Expertboy · 22 Mar 2006

Not used this stuff as i prefer to replace. As far as i am aware it would block a "pin hole to air" but not in a cylinder coil, if a customer asked me to do this i would be advising to replace, because even after it's sealed i have heard within time it leaks again.

I maybe way off the mark here, just going on what some of my colleagues have said.

corgiman · 22 Mar 2006

must say that I have used it, with variable results.

as long as it is a wee small leak then its good, anything bigger you may as well melt some smarties and inject them for the good it does

wont work on the coil though.

if you can see the leak repair or replace dont use the stuff as there is no point

HarrogateGas · 22 Mar 2006

I find on a pressurised system any loss of more than a bar pressure every month and it wont do it..any less and its quite successfull.

Soggy_weetabix · 22 Mar 2006

I double dosed a pressurised system that lost a bar in a week and now (a year on) no pressure drop.

Guess you can be lucky or unlucky with that stuff.

I did mix it with jamaican ginger cake and treacle though.

David

corgiman · 22 Mar 2006

lol

really it held wow, i would never have that luck

ACOperson · 22 Mar 2006

I double dosed it on a fairly large system losing 1.5 (ish) bar per week under posh laminate floor which could not be lifted, it worked!

Great eh!

Slogger · 23 Mar 2006

1/2 a bar in a month and no joy on a pressured system

had to go under the boards to finc the culprit which was a compression joint tiny weep made the customer weep with the bill took me 3 hours crawling like a commando

spose for the costs of this stuff it was worth the try or was it

Dublet · 29 May 2008

I tried it just last weekend (May 24th) and this was to seal 2 very minor weeps. One was on the outlet connection of the heat exchanger on an indirect cylinder and the other to seal a weeping pump connection. Happy to advise both sealed up instantly. Obviously this works in a similar manner to the "Radweld" one used to pour into car radiators when they leaked or the white of an egg!
The pump connection was accessible whereas the cylinder connection isn't. No problems elsewhere and all vents are openable and behaving entirely correctly. I guess the purists will throw their hands up in horror but for a tenner and an hours work draining/re-filling the system problem solved. Obviously I can't say there will be no long term implications but for the time being I am a very happy chappy.

petit_pablo · 29 May 2008

Use it occasionally on systems with history of dropping pressure with no obvious signs of leaks. Usually find its on old systems converted from open vent to sealed.

Have probably a 75% success rate, works particularly well on old cast iron heat exchangers if they have a weeping gasket

hopeforhappiness · 13 Jun 2010

Had a yearly checkup for the central heating. I complained about a leak where I have to repressurise twice a week.
He blythly said get some Fernox and follow the instructions. Got the Fernox, can't get it into the radiator.
The instructions say remove the airvent pin (that's all it is and insert the sharp end of the applicator in and push the gunge in using a gun.
Well, I've discovered that on ALL my radiators you can't remove the pin. You can just turn them to release the pressure. This is so you don't lose it, which would make it impossible to fill the radiator.
You can unscrew the 'valve' leaving an inch-diameter holoe. If you insert the gunge in there it will just come straight out!
Any ideas?

transam · 13 Jun 2010

I have used it succesfully to seal a leaking cylinder coil on a sealed system , however on another job were it was used it blocked or restricted a stainless steel heat exc on a condensing boiler , even if it is not succesful , there is a risk to useing it !!!!

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Fernox leak sealer and similar.

Soggy_weetabix

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