Pinholes appearing in rads...

[spamlet]

Hi All: happy new year...

Over the last few months pin holes have started to appear in our ch radiators - which are fairly old, but thought to have been well maintained - inhibitor in system etc.

The holes have appeared in 3 different rads. In the first two I was able to tap a screw and seal them, but now a third rad has developed a pin hole but in this case it is between the two leaves of a double rad, where I can't get at it.

I see that there are some rad sealing products which we could try: any to look out for that are known to be good?

And, how do these sealing products get on with (are they compatible with) inhibitor solutions: can we add both at the same time?

(There has been various plumbing work over the last year or so, and I am not sure of whether those who carried it out drained and/or replaced the inhibitors.).

Cheers, S

[JimK]

sludge in bottom of rads?

Q:- would a leak sealer be able to penetrate throught the sludge to get to the pinhole(s)?

Sounds to have happened a bit quick for a well maintained system...

Cheers JimK

[David WE Roberts]

If the radiators are starting to pinhole through the metal and the surface paint then you either have a few very abnormally weak areas of metal in a massive area of radiator or you are about to have a sieve.

Which do you think is more likely?

I am assuming this is much like the similar problems you get with car radiators and heater cores. Once they are rotten then you can kid yourself that a magic leak stopper will cure all your problems long term or you can start budgeting for a replacement.

I must say that I have never seen pinholing in radiators - even those 25+ years old.

They surely must be very rotten - especially as it is in more than one radiator.

How old is 'fairly old'?

Sadly, I would write them all off and replace as soon as possible - granted that a leak stopper may get you through the next month or so until you can survive without the heating for a few days.

Even so, it should be possible to work your way round the house replacing a radiator at a time without shutting down the whole system.

Comiserations.

Dave R

[spamlet]

Hi Jim,

The holes have (so far ) been near the top of the rads, and I have flushed them - when changing most of the copper pipes for plastic a couple of years ago - so sludge is not a problem with the current holes at least. Possibly someone let them get low at some time and left a rusty tidemark? (The rads were here before we were.)

So, do these leak sealers work, and do they mix with the usual inhibitors?

Cheers, S

[JimK]

intriguing - pinholes at the top of rads??! - only ones I've ever dealt with (tho not many) were at bottom near either valve...

pass

JimK

[spamlet]

The first that appeared was near to a spot weld holding the two skins of the rad together, and looked to be due to a flaw bubble in the steel - or maybe splash from the welder. The second was higher up on the sloping outward part of a rad, and possibly a weakness from the folding. The third is at the top between two rads back to back, where I can't get at it.

S

[Dave Liquorice]

I've had 'em near the top in the face of the vertical "tubes" and the horizontal top "tube". I suspect that the system had never had any inhibitor in it and was a good ten years old when the holes appeared, in a couple of rads. I soldered little bits of copper over them, drained the system and refilled with inhibitor no more holes appeared.

[ransley]

Ive succesfully use two park epoxy on my car radiadtor, its under 15lb and 200f so it should work on a boiler radiator. Filling a system and not firing it right away to remove oxygen leads to rust. A boiler should never be drained -refilled and let sit all summer withouts days of high firing. There are stop leak products but the metal is thin.

[Spamlet]

Ive succesfully use two park epoxy on my car radiadtor, its under 15lb and 200f so it should work on a boiler radiator. Filling a system and not firing it right away to remove oxygen leads to rust. A boiler should never be drained -refilled and let sit all summer withouts days of high firing. There are stop leak products but the metal is thin.

I've used epoxy - on the plastic parts of car rads at least - but have never entirely trusted it in places that might lead to total loss if it began to fail - for example in the small 'glove compartment' rads, that only come on when selected.

Have you tried any of the leak stopping products?

cheers, S

[Spamlet]

The rads actually 'feel' quite sound. I did replace one recently as it was too big for the room once double glazed. It was v heavy compared with modern ones but still of a similar design.

We are a bit short of cash at the mo, and not ready for a big refit, so stop gaps are all we are after if they work at all. As there is a wide range in price on the leak stopping and inhibiting chemicals I was just fishing to see if anyone had any good advice on which worked and which to avoid. (We've also got the b' motorised valve actuator packing up for the third time - 'pop' 'pop' 'pop' from the radio for ages every time ch and hw are on at the same time, thanks to those infuriatingly fragile microswitches I've complained about here before... yet more quids down the drain.)

He ho.

S

[Spamlet]

Good idea Dave: I haven't been very lucky with getting solder to stick to old iron in the past but it may be worth a try. On the other hand it might make the hole bigger...

My technique with the earlier holes was just to drill and tap them and glue in a small screw, but in the current example there isn't room for this.

Still nobody seems to have much to say about the leak stopping and inhibiting chemicals. Shame as they are quite expensive to just 'suck it and see'.

Cheers S

[Graham.]

Filling a system and not firing it right away to remove oxygen leads to rust. A boiler should never be drained -refilled and let sit all summer withouts days of high firing. There are stop leak products but the metal is thin.

My system has never had inhibitor added, not for the last 30 years anyway. Not been drained for over 10 years either. Open tank system so I suppose some new water would have been introduced to replace evaporation.

My thinking is the water will be pretty inert by now. What do you think?

[Dave Liquorice]

Clean well back to bright metal, acid flux and enough heat. You'll need to drain the radiator so there isn't any water nearby or won't stand a chance.

TBH I can't remeber how I stuck the little bits on now, it was 20 odd years ago. No great areas of burn paint so I didn't use a blow lamp. I don't think my 25W electric soldering iron would have enough capacity. Maybe I used the Portasol gas powered one, that whacks out about 60W flat out. Or it might have be Alradite...

[ransley]

I have gallons on hand for boilers , but I have never needed them, at one location I have a 1,700,000 btu boiler. Here in the US we dont drain down water boilers, if you do it must be fired right away to remove the Oxygen, and fired for a long time, so its only a good time to do it just before or during heating season. There are stop leak products that are cheap, about as much as a cheap bottle of Whiskey or a gallon of antifreeze, they work if the leak is small. But first thing is keep the Pressure-Altitude of the water at the minimum needed to get water to the highest radiator, I only need 15lb to go up 30ft or 3 stories.

is where US boiler pros are, post on The Wall for better info, im just a owner not a repair tech, but my radiators are near 90 years old. here we dont add treatments unless its bad water, maybe your water has chemicals in it that are corrosive. I know one boiler I have the install manual states if water is corrosive or extremely high in mineral content Distilled water should be used. High mineral content leads to scale and popping that reduces efficency and might ruin a boiler eventualy. Big systems are monitored. try

[Spamlet]

I find a miniature blow lamp can get small areas of a big piece of metal hot enough for solder - but making it stick is another matter. Brazing would be better, but I have heard next to nothing about this since I was at school >

40y ago! S

[Spamlet]

I have gallons on hand for boilers , but I have never needed them, at one location I have a 1,700,000 btu boiler. Here in the US we dont drain down water boilers, if you do it must be fired right away to remove the Oxygen, and fired for a long time, so its only a good time to do it just before or during heating season. There are stop leak products that are cheap, about as much as a cheap bottle of Whiskey or a gallon of antifreeze, they work if the leak is small. But first thing is keep the Pressure-Altitude of the water at the minimum needed to get water to the highest radiator, I only need 15lb to go up 30ft or 3 stories.

is where US boiler pros are, post on The Wall for better info, im just a owner not a repair tech, but my radiators are near 90 years old. here we dont add treatments unless its bad water, maybe your water has chemicals in it that are corrosive. I know one boiler I have the install manual states if water is corrosive or extremely high in mineral content Distilled water should be used. High mineral content leads to scale and popping that reduces efficency and might ruin a boiler eventualy. Big systems are monitored. try _______________________

Thanks for the extra info Mark. 90 year old rads is quite impressive. Our system is not pressurised, though obviously the pressure in each rad will vary with how the balancing valves have to be set, and how fast we run the pump. We always use the minimum speed we can get away with (Full speed makes the system overflow - one other way that the inhibitor chemicals could become diluted.)

Cheers, S

[Spamlet]

I don't know Graham, but if the pipes and rads I have changed over the years are anything to go by, you will have a lot of sludge, and it can take an awful lot of flushing to get it out as the coppery black goo is pretty heavy. As to corrosion, obviously the local water supply varies in hardness and mineral content, but even this is pretty closely controlled these days. There are probably electrical/ionic effects that can cause local corrosion if all the metal is not uniform, in any system. But not being chemist or engineer these are only assumptions.

Cheers, S

[Spamlet]

[Spamlet]

Well, never did find out about the effectiveness or otherwise of inhibitors/leak stoppers. But it did eventually dawn on me that the 'doubleness' of the rad actually makes a temporary fix easier: just cut a cork down to a little wider than the gap between the two layers and slide it in over the pinhole. That will do for now!

Cheers, S

[JimK]

nice lateral thought!