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Replacing old HW cylinder

Our HW cylinder is about 37 years old; and since it's starting to leak and has become a bit crusty around the in/outlets for the water from the boiler, I suspect it's well past time to replace it. Years ago, I'd have just replaced it with something similar, but I'm wondering if there is a better option nowadays. I'm interested in thermal store mains pressure cylinders, but it has occurred to me that such a thing may require its own electricity supply (like a power shower might). There is a mains connection in there for an existing immersion heater, and I can find no trace of a dedicated power feed for it; but it seems that the thermal stores have two immersion heaters. Has anyone here ever fitted such a thing? The required plumbing seems straight-forward, but getting another electricity feed in there would not be trivial :-)

Reply to
The Hanging Baskets of Babylon
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My thermal store has the one heater. Perhaps it might be an idea to provide a URL to one you're considering. I suspect the idea is that one is a top-up and the other is for a full cylinder of hot water.

There are two sorts of tanks, one where the tank is unvented and at mains pressure, the other where the tank is vented, with heat exchange pipework at mains pressure.

Both provide hot water at mains pressure.

I went for the second option as they don't need servicing every year.

Reply to
Fredxx

Well, I've only been looking at them for a few hours, and I imagined that this would be typical:

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But if there is one with a single heater, I'd be happy with that; after all, the single heater we already have provides hot water very quickly on the occasions that it's required to, and I don't see why the operational differences should affect that too much.

I'd be going for the vented type for several reasons: no need to inform anyone; 'seems' safer to a cautious type like me; and yes, no servicing.

May I ask which model you have?

Reply to
The Hanging Baskets of Babylon

Fredxx snipped-for-privacy@spam.uk wrote

Why do you believe that the first type requires servicing every year ?

Mine doesn't.

Reply to
Rod Speed

When I replaced a hot water tank I bought one that was covered with 2" of foam so that it would lose to much heat.

Reply to
Michael Chare

Something to do with UK regulations.

Do you live in the UK, or some colony populated with criminals?

Reply to
Fredxx

Your own link says that one is used for boost, the other for off-peak heating.

Sorry, I don't know offhand and not currently in the property. I thought it was a Gledhill, but I bought it second hand, very cheaply.

Reply to
Fredxx

Fredxx snipped-for-privacy@spam.uk wrote

Gotta cite for that, google can't find it.

Reply to
Rod Speed

Nope, you probably can't.

First hit, there are lots of others, if you try looking:

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It might help to use
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Reply to
Fredxx

I presume that that was meant to read "wouldn't".

That caused me a problem. My existing HW cylinder sprang a leak and needed to be replaced. It was a bare tank that had had two jackets placed on it, but I could not source another tank of the same size without pre-applied insulation - which meant that the tank could not be manoeuvred through the very tight clearances, although the final space was adequate. That resulted in me having to cut off a whole load of central heating pipes, valves and the pump. change the tank and then replace and re-join everything. A bare tank would have just slid though (the old one came out okay).

Reply to
SteveW

Fredxx snipped-for-privacy@spam.uk wrote

You clearly can't either.

Doesn't say anything about UK regulations requiring annual inspections.

Try again.

No it does not.

Reply to
Rod Speed

If were capable of using Google you would have been able to find standards such as BS EN 806 and BS 8558:2011

Feel free to show any UK article that says servicing of unvented cylinders of greater than 15litres is unnecessary.

No, you wouldn't find it any help.

No it probably doesn't.

Reply to
Fredxx

Thanks. I guess the off-peak would be used with a timer, and that's something I've never considered since we don't use a tariff that prices off-peak usage differently to daytime (although I suppose this could also just be a matter of collective social responsibility rather than pricing). Perhaps it means that I do not even need to connect one of the heaters. I need to do more research - this is a new subject for me.

Reply to
The Hanging Baskets of Babylon

Fredxx snipped-for-privacy@spam.uk wrote

I did, and realise that neither is a UK regulation that REQUIRES annual inspections.

Irrelevant to your pig ignorant claim about UK REGULATIONS.

It produces the same result as the search terms that include UK, f****it.

Reply to
Rod Speed

You really don’t want a bare tank though. Even with added jackets they lose a lot of heat. Our foam insulated tank gets heated for two hours every night at cheap rate finishing at 01:30 and provides piping hot water all day (and into the evening).

Tim

Reply to
Tim+

I was expecting a silly answer like that. Next you'll be saying that BS

7671 has no basis in law either, and isn't a set of regulations for the UK. I'm sure Adam would agree with you.

Whether you like it or not, many regulations do have a basis in law and so be referred to as UK regulations.

Even ones covered by standards of workmanship are typically called UK regulations. Venture outside of them and see if your house insurance will cover you.

That's a no then. No surprise there.

Try using a Tor based in the UK before looking even sillier than normal.

Reply to
Fredxx

Much of our airing cupboard incorporating the cylinder is unusable from it's location adjacent to bathroom furniture. I had considered stuffing the whole volume, bar a small part with the zone valves and pump, with duvets and blankets.

Reply to
Fredxx

The old double-jacketed tank seemed to hold heat for about as long as the pre-insulated one. Possibly it being in a cupboard with stored bedding, etc. above and quite tight fitting doors helped.

Reply to
SteveW

If the airing cupboard was big enough, one could line the walls, ceiling and floor and door with 150 mm thick celotex....

If space is at a premium and airing cupboard walls are stud and partition, one could remove all internal plasterboard, put in celetox between studs, fit new plasterboard and skim over.

Reply to
SH

Sounds like it...

That depends on how it is setup. Some extract the stored heat with a heat exchanger coil that passes through the water in the cylinder - those will work with just the mains pressure on the DHW, and don't require a separate pump.

Others that use a separate external plate heat exchanger (PHE), will need some way to circulate water from the cylinder through the PHE. Here is a typical heatbank cobbled together from generic parts:

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The pumped options can transfer heat faster (with a big enough PHE) and probably extract a bit more from the store by circulating the water a bit.

Some might have three - they are often configured with one only heating the top bit to give fast "top up" recharges, and a lower one for full store heats.

Alternatively it can be a way of getting faster recharges when used all at once to raise the rate of heat input from 3kW to 6 or 9kW

I considered it, but in the end decided that an indirect unvented cylinder was less fuss.

(the servicing requirements are trivial, and take all of 5 mins)

Reply to
John Rumm

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