Adding Fernox

[Roger465]

Please bear with me when you read this – for the avoidance of doubt, (a) I don't know what I’m talking about, and (b) I know I should get a proper plumber to do it. Trouble is, the one we used for years let us down very badly, skimping on things, bodging etc – took us a long time to realise what a cowboy he was. And it seems impossible to get any other one to come out for anything short of supplying a new boiler etc. If I could, I would – believe me.

OK. I moved into this house 6 years ago, and had a new oil boiler fitted. It works well, but there’s one perplexing problem. The small kitchen radiator fills up with air quite quickly. I’ll be sitting there, and suddenly there’s a big loud gurgle. This will happen several times over a few weeks or whatever, and it gradually fills with air. I asked the old plumber about it at least a couple of times, but his standard response was “Meh – don't worry about it.”

Somebody suggested it might be hydrogen, but I’ve held a match to the bleed nipple when the gas is coming out, and no bang. Also, not sure a fault could generate enough hydrogen to fill a rad in a couple of days?

So I assume there has to be a leak. None of the other rads have needed bled in 6 years. But there’s no pool of water, or dampness anywhere in the house. The pipework comes up out of concrete flooring, so I assume it’s kind of sealed in concrete?

It doesn't bother me having to bleed the thing from time to time. But I realise as the system is constantly replacing its water from the little header tank in the attic that the Fernox stuff must be constantly getting diluted, so there’s probably none left now.

Unfortunately, due to a spinal problem, my days of crawling into attics are over. So I wonder… when the rad is nearly empty, could I squirt Fernox into the kitchen rad through the bleed nipple hole while it’s filling up, and so refill the system that way? I have some old hypodermics I could use…

Thanks

 

[Harry Bloomfield]

Unfortunately, due to a spinal problem, my days of crawling into attics are over. So I wonder… when the rad is nearly empty, could I squirt Fernox into the kitchen rad through the bleed nipple hole while it’s filling up, and so refill the system that way? I have some old hypodermics I could use…

You could....

Turn both of the radiator valves off first, to prevent the radiator refilling, as you try to put the Fernox in.

 

[Roger465]

Thanks Harry, you're a lifesaver as usual.

Just out of curiosity... I understand that each rad in the house is fed by a separate pipe under the floor from a big junction box somewhere?

As none of the other rads ever need bled, is it reasonable to assume that there will be a leak in that pipe somewhere?

And if so, the only solution would be to have the floor taken up

My logic is that, if the leak were anywhere else, I'd have a damp patch.

Oh, and I see Fernox do a leak repair product as well, like the stuff people like me remember putting their car rads back in the 70s
wonder if it's any good...?

 

[Burnerman]

Have a look at Fernox F1 Express.......it's so easy to inject.
Turn both rad valves off, insert the F1 applicator, and as you pump it in, release the pressure by opening one of the valves slowly.
Of course, the gas in youyr system may be coming from the muck that is sure to be in there.......when you bleed, is the water black at all?
John

 

[Roger465]

Have a look at Fernox F1 Express.......it's so easy to inject.
Turn both rad valves off, insert the F1 applicator, and as you pump it in, release the pressure by opening one of the valves slowly.
Of course, the gas in youyr system may be coming from the muck that is sure to be in there.......when you bleed, is the water black at all?
John

Will do, thanks. Think the water is pretty clear actually!

{edit} hmmm looks like I'd need 2 of those, as I have more than 9 rad panels in the house...

 

[Burnerman]

It could be worth while removing the radiator for a good flush out with the garden hose.....if that's convenient, just to see what's actually in there.
John

 

[Harry Bloomfield]

Just out of curiosity... I understand that each rad in the house is fed by a separate pipe under the floor from a big junction box somewhere?

Unlikely, more usual is a larger diameter pipe (22mm), with branches of 15mm T'ed off to the radiators.

As none of the other rads ever need bled, is it reasonable to assume that there will be a leak in that pipe somewhere?

Again, unlikely - more likely it is either air being drawn in, or hydrogen being created. What sort of system s this - combi/open vented or etc?

 

[Roger465]

It could be worth while removing the radiator for a good flush out with the garden hose.....if that's convenient, just to see what's actually in there.
John

Any attempt by me to do something like that usually results in a biblical flood

Unlikely, more usual is a larger diameter pipe (22mm), with branches of 15mm T'ed off to the radiators.



Again, unlikely - more likely it is either air being drawn in, or hydrogen being created. What sort of system s this - combi/open vented or etc?

It's an oil boiler, and not combi. I think open vented means the old fashioned (installed 1994) kind with a hot water tank... is that what you need to know?

 

[Harry Bloomfield]

I think open vented

It could be due to pumping over - the pump pumping too hard, pumping hot water up the vent, back into your small header tank - in the process, introducing air into the system. Check when the system is running, whether the small header tank in the loft, is getting warm/ has water flowing into the top of it via the vent pipe. The vent pipe goes up higher than the tank, then back in via the lid. Fix might be one of simply turning the pump speed down.

 

[Roger465]

It could be due to pumping over - the pump pumping too hard, pumping hot water up the vent, back into your small header tank - in the process, introducing air into the system. Check when the system is running, whether the small header tank in the loft, is getting warm/ has water flowing into the top of it via the vent pipe. The vent pipe goes up higher than the tank, then back in via the lid. Fix might be one of simply turning the pump speed down.

Thanks again Harry - trouble is, I'm no longer capable of getting into the attic. I did turn the pump down from position 3 to 2 a year or two ago, just to see if it would make a difference... it didn't. Maybe I should turn it down to 1 just to see if that makes a difference.

This is a bungalow, so the header isn't as high above the boiler height as it might be in a 2-storey house...

 

[Harry Bloomfield]

Thanks again Harry - trouble is, I'm no longer capable of getting into the attic. I did turn the pump down from position 3 to 2 a year or two ago, just to see if it would make a difference... it didn't. Maybe I should turn it down to 1 just to see if that makes a difference.

Turn it down to the minimum, which offers enough flow, to heat your house.

 

[Roger465]

Have a look at Fernox F1 Express.......it's so easy to inject.
Turn both rad valves off, insert the F1 applicator, and as you pump it in, release the pressure by opening one of the valves slowly.
Of course, the gas in youyr system may be coming from the muck that is sure to be in there.......when you bleed, is the water black at all?
John

Well I tried. Hypodermic it is then.
This is what we have to put up with in NI

 

[Roger465]

So... I turned the pump down to (1), and am surprised to report that it seems to have made very little difference to the speed the rads heat up, so you may have been right about that one

I'll report back in a week or so if the rad has stopped filling up with air. It's odd how it happens... every so often I hear a great gurgle from the kitchen, as the rad lets a pile of air in - eventually ending up more or less empty. Haven't heard it since slowing the pump down, but it's less than 24 hours.

Getting 500ml of Fernox in using a 10ml syringe was a bit of a laugh, but got there in the end