Costly Cylinder - alternatives ?

[Jeff]

I've just been quoted £575 including vat for an Albion Superduty CF210 cylinder. What are the alternatives to provide similar fast recovery and capacity (210 litres)?

[Doctor Evil]

Try:

(make cylindrical thermal stores) (make square stirage vessels) (make heat banks and storage vessels to size) (make thermal stores and stioarge vessels) (make cylindrical heat banks and storage vessels) (make heat banks and storage vessels) (make cylindrical thermal stores and storage vessels. They are quite cheap) (make cylindrical thermal stores and storage vessels)

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[Jeff]

Thanks, I've considered the vented thermal stores but on balance I think I'm committed to a standard vented cylinder. I've got loads of long dead legs so I'm planning a pumped dhw loop with a return tapping in the cylinder. I don't think you can do this with hot water at mains pressure, can you?

So my question really is - is this an awful lot of money to pay for a regular albeit high performance cylinder, and are there alternatives, ie, cheaper cylinders? Or is this just the price of a cylinder nowadays?

[Doctor Evil]

Yes you can have a secodnary circulation loop on a heat bank/thermal store. Christian fitted a DHW only Pandora heat bank. He swears by it. Try Newark who make reasonably priced thermal stores. Dircet from the makers.

There are cheaper makers around. Try the list I gave. Get quotes for a quick recovery cylinder and a direct thermal store.

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[Paul Barker]

Paul Barker

[fred]

In article , Jeff writes

I was there about 2 years ago and in the end got a Range Supercal 206litre via discounted heating for 350quid. They don't list Range cylinders on their site but I had used them for a big order and called them to see if they could source one anyway. They said no problem, got me a quote & delivered in about 4wks.

I talked with Range's technical department extensively before I placed the order and they were v helpful. If you are looking for a custom, I would suggest contacting them first, exchanging drawings, getting a custom design ref, then getting the quote through discounted. A google will get you Range's site & numbers.

discounted act as agents for Plumbcenter so if you can find it on that site/catalogue you should be able to get it from them. I think I did check the price for an Albion but it was through the roof.

ps: recovery is no problem, the cyl can soak up the full 25kw from my boiler with no problems.

pps: I assume you will be super insulating the circulation loop?, then I reckon you only need to circulate at a rate which will compensate for the (v small) losses in your pipework. If they were suitable for the job I reckon a windscreen washer pump would have enough capacity to circulate a well designed loop.

[mike ring]

"Jeff" wrote in news:cu2ki4$hca$1$ [e-mail]:

Try BHL 0870 4586288.

They have a website, but I found they could get me everything I requested.

I'm not current on big old cylinders like you want, but they got an impressive discount on all my gear, including a CF80

I went to plumbsomething at Chelmsford, was gobsmacked by the price, found this lot, ordered, and the tank was delivered from plumbsomething at Chelmsford on their van with their delivery note, but much cheaper.

I'm NOT saying they're the cheapest, but they're helpful, knowledgeable, keep their promises (or get the hump with the local suppliers).

(Tell Lee mike sent you - he might send me a fiver)

mike

[Dave Plowman (News)]

Use two or more conventional fast recovery cylinders?

[Jeff]

Well, I've had a quick look at the links you and others have provided, and a search on the post by Christian and his Pandora installation. His is not a dhw loop, though, from his description.

This has all re-kindled my interest in reverting to a thermal store system, though, but I still haven't established how the dhw loop works when the hot is really just heated mains water. I cannot find any reference to dhw loops on the Albion site.

Can you just give me a few clues so that I know what to look up please ?

[Doctor Evil]

Unvented Cylinder & Vented Cylinder.

Fit a secondary circulation loop from the draw-off at the top back to the cylinders tapping on the side of the cylinder, which will be near the top, which is sometimes the shower tapping. Take all the taps off this loop. Use a dedicated pump (grundfos make one), or a normal CH bronze pump near the cylinder return. Install a pipe stat near the pump set to 40C. If above 40C the pump is switched off. Also have a timer on the pump to switch off at night. This is the same for an open vented or unvented cylinder, if there is a tapping on the side of the cylinder

Unvented Cylinder

If no tapping on the side of the cylinder, then you have to use the cylinder cold feed from the mains, after the pressure reducer, if one is fitted near the cylinder. As above, but a check valve on the cold feed to the cylinder (one should be there anyhow) after the check valve the secondary loop tees in. On the secondary loop pipe before the tee into the cold feed fit another check valve. The pump must be before the check valve on the loop. Fit a shock arrestor on the loop near the cylidner (available

Bank/Thermal store

Fit a secondary circulation loop from the hot draw-off back to the mains cold feed, after the pressure reducer, if one is fitted. As above, but fit a check valve on the cold feed to the heat bank/thermal store, after the check valve the secondary loop tees in. On the secondary loop pipe before the tee into the cold feed fit another check valve. The pump must be before the check valve on the loop. Fit a pipe stat on the loop near the pump and set to 40C. Fit a shock arrestor on the loop near the cylinder (available

of one not already fitted on the heat bank.

The draw-off/secondary loop "must" be well lagged

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[Doctor Evil]

Unvented Cylinder & Vented Cylinder.

Fit a secondary circulation loop from the draw-off at the top back to the cylinders tapping on the side of the cylinder, which will be near the top, which is sometimes the shower tapping. Take all the taps off this loop. Use a dedicated pump (grundfos make one), or a normal CH bronze pump near the cylinder return. Install a pipe stat near the pump set to 40C. If above 40C the pump is switched off. Also have a timer on the pump to switch off at night. This is the same for an open vented or unvented cylinder, if there is a tapping on the side of the cylinder

Unvented Cylinder

If no tapping on the side of the cylinder, then you have to use the cylinder cold feed from the mains, after the pressure reducer, if one is fitted near the cylinder. As above, but a check valve on the cold feed to the cylinder (one should be there anyhow) after the check valve the secondary loop tees in. On the secondary loop pipe before the tee into the cold feed fit another check valve. The pump must be before the check valve on the loop. Fit a shock arrestor on the loop near the cylidner (available

Bank/Thermal store

Fit a secondary circulation loop from the hot draw-off back to the mains cold feed, after the pressure reducer, if one is fitted. As above, but fit a check valve on the cold feed to the heat bank/thermal store, after the check valve the secondary loop tees in. On the secondary loop pipe before the tee into the cold feed fit another check valve. The pump must be before the check valve on the loop. Fit a pipe stat on the loop near the pump and set to 40C. Fit a shock arrestor on the loop near the cylinder (available

of one not already fitted on the heat bank.

The draw-off/secondary loop "must" be well lagged

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[Christian McArdle]

Note that I didn't have a secondary circulation loop. However, it was a factory fitted option.

Christian.

[Christian McArdle]

It makes no difference what sort of system you have when fitting a circulation loop. When all the taps are off, the pressure at the cylinder and the pressure at the tap are the same (ignoring height effects). Therefore, a simple low power, low head pump can circulate the water back whether it is gravity fed at 0.2 bar or mains fed at 3 bar. Just a tiny 0.1 bar pressure differential would be enough to recirculate in each case.

The main problem I could see with a heat bank is that running the exchanger pump would cause destratification. However, I wouldn't be surprised if they had designed the system to deal with this issue. It may even be that parasitic effects are enough to keep the recirculation loop hot, without needing to run the plate exchanger pump, but I don't know how it is designed.

Christian.

[Doctor Evil]

When installing a secondary circulation loop on a heat bank the loop can be fitted on the return above the flow switch (if one fitted), It really doesn't matter that much if the heat bank blending valve is say, set to 55C and the loop pipe stat is set to 40C. Draw -off water will heat most of the loop to 55C, the pump will energise below 40C and drag in 55C water. So, it will take a time to cool down, and any re-stratification can recovery in that time. Some heat banks have spreaders in inside to avoid server de-stratification. Gledhill's modulate the pump to exactly what speed is required to maintain a temperature. This also avoid excessive de-stratification.

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[Doctor Evil]

Did they tee in the return of the loop before or after the flow switch?

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[Jeff]

OK, the reference to exchanger pump had me puzzled - the Albion thermal stores have no pump. Is there an advantage in the Pandora system of pumping the water across the plate exchanger when flow is detected? Don't most thermal stores do the heat exchanging within the main body of water? The Pandora system seems to be adding complexity, I guess there must be a reason for it.

To return to the loop question, I presume I should tee in the return on the cold side of the mixing valve - so that the circuit does not trip the flow switch when hot water is simply circulating?

Christian, in Oct 2003 you said: " Flow rates are higher than my old gravity system into the bath (but not really a patch on my parent's Megaflo or the pumped gravity system in my previous house "

I'm still getting the impression that to get the fastest bath fill up possible, I use a standard vented cylinder and big bore pipes. For showering, I can get at least 2m between the base of the cold feed tank and the shower rose. What's your opinion ?

[Gordon Henderson]

Theres an Albion with an Internet coil rather than an external exchanger and pump, which I have looked at in my quest for information about thermal stores, etc. From the Albion web page it would seem that the exit temp from thte coil would be 50C, but from other sources, the exit from a plate heat exchanger would be closer to 70C, but I guess it depends on other factors - probably mostly flow rate.

The Internal coil has the advantage of not disturbing the water in the tank as much as the external plate heat exchanger & pump, but at the end of the day, who knows whats best?

The Albion would certinaly simplify plumbing and save on one pump, thats for sure, but at the expense of how much efficiency, I wonder?

Gordon

[Gordon Henderson]

Of-course, I mean internal coil ...

[Doctor Evil]

Yes. Plate heat exchangers is far more efficient than an immersed coil, so will give higher flowrates. Plate heat exchangers can be taken off and de-scaled. Also have a full bore isolating valves either side, to avoid a drain down and having to pay £30 for inhibitor. The makers may do this as an extra.

Yep.

Higher flowrates. The Pandora also does not require a F&E tank or overflow. It is filled with hose pipe. Very DIYable.

Remember, if you have a pipe stat on the loop it will cut out the secondary loop pump when over 40-45C, so it really does matter that much.

Depends on the mains presssure, size of main, etc. A heat bank can outpeform an unvented cylinder by adding another plate in parrallel. This can be easily retrofitted. You can't do that with a coiled thermal store.

A tank/cylinder setup will give a fast bath fill with large bore pipes, but a heat bank, providing the mains can cope will give all you wnat.

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[Doctor Evil]

Shouild be doen't not does.

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