Direct hot water cylinders

I've just found that our hot water cylinder is weeping from the joint between the body and the top. Since it's over 40 years old (I assume), it's probably simpler to replace than repair. Now, I'm sure there are rules about who can and can't do this, so let's assume that I'm buying one and getting a plumber to fit it, in the same way as I would never do anything electrical or with gas fittings (!).

The house has hot air heating (sadly), which means it's immersion heater only for the DHW. I have no intention of changing this as the house is going onto the market soon and I don't want to start any new major jobs.

Anyway, I've never played with hot tanks before but this is clearly a direct cylinder. Screwfix do what seems to be the best buy (

formatting link
but the description says it has a 'large heating coil', which sounds wrong for a direct cylinder to me: Is this a typo or am I missing something?

The real question: Does anyone know if the location of connections (cold in, hot out, immersion heater) is standard? If there's any choice, I'll investigate the market to see what's the easiest fit.

Similarly, is there anything to consider in terms of immersion heater elements? I seem to recall reading that modern cylinders can have two heater bosses and, presumably, this means they can be heated faster. All the elements I can see (eg TLC) are 3kW: Seems to me that 2 x 3kW is too much for the existing 20A supply. Does that mean I have to run another 20A feed or is it reasonable to just cap one boss off? (We've got by for years with one element and I'd rather not have to feed it with a new circuit if I can avoid it.)

Reply to
GMM
Loading thread data ...

No standards that's I've ever noticed - it all seems pretty random. If you shop around, you might find something close that will require the lest fiddling with the pipework.

Element length for one.

I seem to recall reading that modern cylinders can have two

And so that the top one can be used to "top up" the tank. If this is top mounting, vertically alighned, you may expect to want a shorter element. If the other boss is also top mounted, you'd want a long element to reach down the tank. If the bosses are side mounted, one nearer the top and one nearer the bottom then you'll be needed shorter elements so as not to foul the other side of the cylinder.

As heater are cheap, fit two and wire the bottom one only. At least the next inhabitant can wire teh top one if they want faster recover or top up mode. If you're feeling less well inclined to spend money (who isn't right now) cap it off.

Yes, 2 heaters is too much by far for a 20A circuit.

HTH

Tim

Reply to
Tim Watts

Thanks Tim: Probably easier to get a second element than find a plug for a dirty great thread like that anyway and I suppose it would provide an emergency spare to get a bit of HW (with a quick wiring swap) when, as is inevitable, the main element burns out at 6pm on Christmas eve, as they're so often programmed to do......

Reply to
GMM

formatting link
quid, down the bottom :)

having said that, a decent immersion heater is 10-15 squids or so.

Same BES page will give you an idea of lengths available. You'll probably find what you need in B&Q or your nearest plumbing place.

This is a valid point :)

Reply to
Tim Watts

There's a special switch for this purpose...

formatting link

Reply to
Andrew Gabriel

This is silly. Just redo the joint.

NT

Reply to
NT

If it's weeping, it's pretty likely the rest is going to spring more leaks real soon.

Reply to
Tim Watts

That was my thought: it seems that brazing or soldering would simply chase the problem around the seam, possibly to a less visible position (at least it's right at the front just now). On the other hand, it occurred to me this morning that I might be able to buy a little time by bodging something here: I wonder if anyone's had any luck with epoxy or any of the 'metal repair' filler? Obviously would need draining down first but that's hardly a problem.

Reply to
GMM

In article , GMM writes

Given the potential for a big mess if the seam lets go, especially if it's located on an upper floor, personally I wouldn't arse about with it and would replace it asap.

Reply to
Mike Tomlinson

And take it to a few scrap metal merchants and ask them how much they will pay for it. Older tanks have far more copper in them than new ones, and the scrap value can be surprisingly high.

Normally, the plumber claims the scrap value and doesn't pass it on to the customer.

Reply to
Bruce

Maybe I'm the only one that thinks the sensible thing is to have a look at the joint first, see what the situation is, it may save a fair bit of time & work. Epoxy is good stuff, except when exposed to heat. If adhesive is needed due to tank damage, better to go for one of the adhesives designed for use on hot car engines.

NT

Reply to
NT

Yes, you probably are the only one. ;-)

Try concentrating your mind on the reality of the problem by considering *the consequences* of a leak. Having had a leaking hot water cylinder about four years ago which led to some fairly costly damage, I would never consider taking a risk with a joint in an old cylinder.

Reply to
Bruce

We were somewhere around Barstow, on the edge of the desert, when the drugs began to take hold. I remember GMM saying something like:

I've tried the repair types of epoxy putty and they're useless after a few days. I suspect the expansion/contraction breaks the bond.

Reply to
Grimly Curmudgeon

In article , NT writes

Each to his own, but IMO gluing a 40-year-old cylinder is not the most wonderful idea. The cylinder owes the OP nothing.

Reply to
Mike Tomlinson

Although changing a cylinder with one that's bound to have different pipe locations fills me with horror (Helmut Kohl & Anne Widdecome reclining naked on a glass coffee table kind of horror) I agree. *If* I were trying to fix it I might patch some sheet copper on with plumbers metal (as used for lead work) or even just blob some of the same on for a small leak. But the heating is bound to disturb another weak bit and so on... If it's pinholing, there may be potential holes blocked by scale - once that falls off then :-<

Much better to change it and be done with it. It's 40 years, it's had a good life...

Reply to
Tim Watts

I think you're right - a new one is the only sensible thing, and no messing about!

As much as I approach re-routing the old pipework with some trepidation (3/4 to 22mm to god knows what and all the bends etc), it can't possibly be as bad as that glass table can it? Can it? Oh noooooo......

Reply to
GMM

Replace it with a stainless steel cylinder. Some have 25 year guarantees. Or fit a Rinnai multi-point water heater - can be fitted outside liberating space in the house as no cylinder is needed. Then high pressure mains showers. The Rinnai can have a flow switch fitted that cuts out the warm air unit when the hot tap is on to keep the gas under a U6 meter consumption.

In time replace the warm air unit with a modern unit with an electrostatic air filter. The difference is amazing. Much better than rads.

Prepare for the future.

Reply to
Doctor Drivel

Own goal, Drivel - try reading the OP's first post. He wants to sell the house shortly, so clearly doesn't want to make any investment in it for 25 years.

Reply to
robgraham

Own goal, Drivel - try reading the OP's first post. He wants to sell the house shortly, so clearly doesn't want to make any investment in it for 25 years.

Reply to
Doctor Drivel

In article , robgraham writes

Usenet's write-only as far as dribble is concerned.

Reply to
Mike Tomlinson

HomeOwnersHub website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.