Pinhole leak in designer rad/s

diystarter7

Hello.  My friend had a brand new CH system installed about 10-5 years ago.  He used the same designer rads as we did. the rads came with a 10 yr warranty and the first had a pinhole near the top of the rad and the manufacturer kindly supplied FoC a new one but recently two more are about to leak about 3 or 4 inches from the top as pain is bubbling.

I'm worried that mine may leak as well The question is sludge builds up at the bottom if any but to have pin holes near the top, is that because of rust? Their system loses a bit of pressure reason not known just like ours, we both top up once a year 

Any ideas, please?  (They a Ximax Oceana rads - We paid a lot close to 11 years ago when hardly anyone had them but looking at the prieces now it is staggering as we have mirrored one and all are double and a good 5 to 6 foot long. Thanks again

Bendy_House

Hi Starter.

The fact that their rads are failing doesn't mean that yours are going to.

There are two obvious causes of these pinholes. The first is a manufacturing issue with the welds at that point. Are the leaks on or around these welds? Ie, where the verticals join the top horizontal rails?

The other possible cause is corrosion, and this will be taking place from within the rads.

They were lucky that the manufacturer replaced the leaking one, and that suggests they accepted it was a manufacturing fault? I am pretty certain that, if the rads actually rusted, they wouldn't replace them, as internal rust means the system hasn't been protected properly = not their fault!

So, a couple of things to check, please; close-up pics of the pinholes and surrounding area. Can you see where exactly the water is leaking out from? And, open the bleed screws and see if any 'air' comes out. If so, how much - how long does it 'hisssss' for?

Are you a bit of a boff?! Would you be up for catching some of that gas in an upturned mug, and then placing a lit taper to it - see if it goes 'pop!' to reveal if it's hydrogen?

We really need to know the 'cause'; defect or corrosion. The solution will depend on that.

Do they, or you, have a magnetic filter fitted to your return pipe? If so, when was the last time it was checked for sludge?

davemorton

Bendy_House said:

Are you a bit of a boff?! Would you be up for catching some of that gas in an upturned mug, and then placing a lit taper to it - see if it goes 'pop!' to reveal if it's hydrogen?

Utterly intrigued, what would this mean if it did pop.  What reaction is going on to create hydrogen? TIA 
Edit: Excited now to the next time I have to bleed a radiator.

Apodemus

Just because the paint is blistering doesn't necessarily mean pin-holes or that the radiators "are about to leak".  

Bendy_House

davemorton said:

Bendy_House said:

Are you a bit of a boff?! Would you be up for catching some of that gas in an upturned mug, and then placing a lit taper to it - see if it goes 'pop!' to reveal if it's hydrogen?

Utterly intrigued, what would this mean if it did pop.  What reaction is going on to create hydrogen? TIA 
Edit: Excited now to the next time I have to bleed a radiator.

Do you currently have eyebrows?

Bendy_House

davemorton said:

Bendy_House said:

Are you a bit of a boff?! Would you be up for catching some of that gas in an upturned mug, and then placing a lit taper to it - see if it goes 'pop!' to reveal if it's hydrogen?

Utterly intrigued, what would this mean if it did pop.  What reaction is going on to create hydrogen? TIA 
Edit: Excited now to the next time I have to bleed a radiator.

Good Q. Must look it up.

I think there's some fun YouTube clips too

Bendy_House

https://www.youtube.com/watch?v=0GXDKxX9C7E

diystarter7

Thanks all/Bendy House

Pin leaks not at "joints...fixings" etc.

Air does seep into our systems never been able to find a reason.

The bubble is a pressure-related type.

Non of the pin holes were near the bottom ie 12 inches from the bottom.

Mates has a magnetic filter a newer version that you open and clean and ours is like a sausage and fitted when first installed about 11 years ago.

PS. We had a leaky TVR value a couple of years ago and the water was "rusty, dirty" according to the plumber we had the system drained and anti-rust added but previously had not had new anti rust in for a few years and had been topping up

Re pinholes, sludge collects at the bottom does it not so I am surprised pinholes have been higher hup as is the bubble in my rad.

Bendy_House

Sealed - pressurised (with a gauge) or open 'vented' system?

Yes, sludge collects at the bottoms or rads, but that doesn't mean the corrosion occurs there - it can be anywhere. The sludge just settles.

Quite often, on really badly corroded systems, a good system clean will expose other pinholes that were actually blocked by the sludge, so some folk experience leaks after they've had a power-flush/clean...

If the bubble is largely/partially made up of air that has gotten into the system, then I would be surprised if the main rust occurred at that point - there is air and water along that bubble line.

Your sausage - is that really a filter, or is it a scale reducer?

Anyhoo, you need a good, proper mag filter fitted, and a healthy dose of system cleaner. Run this until the bulk of the sludge has been collected and removed, and then add a large dose of inhibitor.

It can be tricky to find out why air gets drawn in. If it's a vented system - an F&E tank in the loft - then some partial blockages can cause the pipes behind the pump to be in negative pressure, and this can sometimes draw air down the vent pipe. Summat like that. Or, if the F&E tank is a bit too low, the system water can sometimes be pumped into it on system start-up, and this mixes fresh air into that water, which then slowly joins the system.

If it's a sealed system, then 'air' getting in is very unlikely. So probably the gas will be hydrogen or similar.

Sounds as tho' you need a good, time-served plumber in to check out the whole system from the ground up.