Copper cylinder question.

I've spotted a very small leak from the top flange on our copper cylinder heating coil. I'm planning to drain the cylinder and push something in the gap this weekend. I'm just wondering if it's possible to get the coil out, or if the cylinders are welded together with it in place. If I could get it out, it would make it easier to clean the mating surfaces, but looking at it, I'd be suprised if it was possible.

Also, does anyone know what would work best? My old and well-used tub of Boss Green (which fixes most things for me), silicone sealer, Plumber's Mait, or something else?

Reply to
Dan S. MacAbre
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solder?

Owain

Reply to
spuorgelgoog

I don't think I could get it hot enough. Do you think it could be done with a blowtorch? I have tried, and failed, to solder other large things in the past.

Reply to
Dan S. MacAbre

Forget all of those, they are unlikely to cope with the pressure. (Well, silicone might but you would need to drain down and get the surfaces dry).

The one thing which should work is the two part epoxy putty made for plumbing repairs, I have used it successfully in a similar situation. (cold feed rather than heating coil). It sticks on a wet surface and (provided the leak is small enough) maintains the seal until it sets. Doesn't look pretty, but very easy and permanent.

If the leak is too fast, drain down first.

Same arguments apply for an immersion heater as for a heating coil.

Soldering might be possible if you know what you are doing, but tank and coil would need to be drained, you probably don't have good access, and the solder probably won't penetrate the leak path even with acid flux, but a patch should work, if done properly.

Reply to
newshound

I have some Milliput somewhere - have you ever seen that? Sounds similar.

Reply to
Dan S. MacAbre

A decent blowlamp should solder it no bother. The copper isn't very thick.

The problem is likely to be cleaning things properly before soldering. And if simply a crack, would need a plate soldered over it.

Reply to
Dave Plowman (News)

Not made for that job, I don't know if it would work on wet surfaces. Just search eBay for "plumber epoxy" and you will find numerous different products. Screwfix doesn't seem to stock any, but any decent hardware store or any plumbers merchant should have something.

Reply to
newshound

Okay, I'll see what I can find. Thanks.

Reply to
Dan S. MacAbre

I'm pretty sure it's just leaking out of the tightened flange. Also, the tank is coated in some sort of foam (which makes it hard to be 100% sure about the origin of the leak), which I would probably end up setting light to :-)

However, I do have blowlamp, solder, and flux, so it'll be on standby.

Reply to
Dan S. MacAbre

You can't get the coil out without taking the cylinder apart.

Where the two ends of the coil emerge from the cylinder there will be a flange on the inside and a fibre washer and nut on the outside. I had a similar problem with my cylinder, caused by one of the fibre washers perishing. I managed to fix it without draining down by slackening the nut and winding some boss-white impregnated hemp behind it, and then re-tightening it.

If you don't mind draining down, remove the external pipe, and then remove the nut and replace the fibre washer - preferably with a neoprene one. You may need to cut away some of the insulation to get at it.

Reply to
Roger Mills

Thanks. No problem draining down - I'll use a garden hose out of the front door.

Reply to
Dan S. MacAbre

Is there a drain c*ck at the bottom of the cylinder? If not, it's not too easy because simply opening a hot tap doesn't drain the cylinder. Also, you'll need to drain the primary circuit before disconnecting the external pipe(s) connected to the coil.

Reply to
Roger Mills

I think it's reasonable to assume that if he's planning on using a hose pipe, he isn't intending to try draining it via a hot tap.

Tim

Reply to
Tim+

Yes, there's a drain c*ck in the lowest part of the HW exit pipe that will do nicely. The HW/CH system is already drained, since I've just replaced a couple of radiators downstairs. The cylinder job is something I'm doing "while I'm at it". It's a tiny leak that I've just left a piece of kitchen roll under for now, and that has been enough, but now seems like a good time to fix it.

Reply to
Dan S. MacAbre

Oops, I mean the CW inlet pipe. The HW comes out at the top, of course.

Reply to
Dan S. MacAbre

If it's brazed or soldered joint, then cleaned up of oxidation and soldered. If it's a mechanical joint it will have to be dismantled, cleaned and fresh jointing material and paste fitted.

Plumbers Mait is good stuff.

Reply to
harry

In article , Dan S. MacAbre scribeth thus

If its any age I'd suspect that there are other places where it might star to fail or leak. Might be best to bite the bullet and replace it than to patch it....

Reply to
tony sayer

Yes, it's a mechanical joint. There's a very small dribble coming out of it, and there's a small damp patch on the board underneath it. The annoying thing is, it's going to be hard to clean up the mating surface on the inside through the small gap that will be available when it's undone.

Reply to
Dan S. MacAbre

It's about 30 yrs old. It's covered in an insulating layer of foam which is good, I suppose, but which makes it hard to inspect.

Reply to
Dan S. MacAbre

I'd be inclined to replace it. IME it's probsbly getting close to the end of it's life and it's easier to do it while the whole system is out of commission and in summer. A new cylinder may have a better heat exchanger than your old one.

Reply to
Capitol

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