Mon, 25 May 2026 12:05:04 +0100 https://www.greenbuildingforum.co.uk/newforum/ Lussumo Vanilla 1.0.3 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=1649&Focus=19588#Comment_19588 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=1649&Focus=19588#Comment_19588 Tue, 29 Apr 2008 15:34:14 +0100 Ads
However, a number of issues have been raised and I wondered whether anyone here can help:

How much more expensive would a thermal store be compared with a replacement conventional or combination boiler?
How is a thermal store sized correctly?
Can a water softener be utilised (their's is a hard water area)?
DPS seems to have been used by a few members here, who else should we look at and does anyone have any words of wisdom?
Solar input is not likely to start with, but may be later on. Can suitable inputs be incorporated at installation without adversely affecting the system should solar not appear for a while?

I appreciate that a lot of this is probably quite basic stuff, although most plumbers seem to be rather bemused by the concepts, but all comments welcomed.]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=1649&Focus=19620#Comment_19620 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=1649&Focus=19620#Comment_19620 Tue, 29 Apr 2008 18:58:05 +0100 tony How is a thermal store sized correctly? Tisnt usually! Similar size to a large HW cylinder will be ok -- best if it will fit in airing cbd and 3x as much insulation
Can a water softener be utilised (their's is a hard water area)? Yes
DPS seems to have been used by a few members here, who else should we look at and does anyone have any words of wisdom? Buy a large new HW cylinder and have extra tappings put in at time of manufacture and additional spray insulation or adapt a s/h one.
Solar input is not likely to start with, but may be later on. Can suitable inputs be incorporated at installation without adversely affecting the system should solar not appear for a while? Yes see above.]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=1649&Focus=19635#Comment_19635 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=1649&Focus=19635#Comment_19635 Tue, 29 Apr 2008 21:01:08 +0100 SimonH I think an unvented tank wouldn't be much less. A standard insulated copper cylinder would only be around £200 though.
Or you can go bonkers as fit a 500l consolar for about £2000.]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=1649&Focus=19639#Comment_19639 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=1649&Focus=19639#Comment_19639 Tue, 29 Apr 2008 21:16:28 +0100 Dantenz https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=1649&Focus=19661#Comment_19661 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=1649&Focus=19661#Comment_19661 Wed, 30 Apr 2008 09:45:11 +0100 Mike (Up North)
Firstly a thermal store or heat bank provides mains pressure hot water without having the potable stored water held at mains pressure, this is what an “un-vented cylinder” does. An un-vented cylinder stores the hot water DHW at mains pressure. Consequently it falls under pressure regulations that require a safety valve, expansion vessel etc etc this must only be installed by a fitter with the necessary “ticket” (bit like corgi) and subsequently maintained by the ticketed engineer. A thermal store does not require this as the body of stored water is un-sealed; the potable DHW is only in the heat exchanger loop pipework so does not fall under the regulations. Because of this pressure they are usually glass lined steel or stainless steel and would cost anywhere from £500 to £1000 ish. Which is about the same as many thermal stores except they are usually in copper. Albion Mainsflow for just DHW is an example thermal store as an off the shelf item.
A thermal store is best for combining inputs as heating load is distributed from the central point. Another benefit is that if you are using oil fired which cannot easily be modulated down as temps rise, short cycling which is wasteful can occur. The thermal store presents a fixed volume load to the boiler which allows for much steadier running.

Cheers, Mike up North]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=1649&Focus=19665#Comment_19665 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=1649&Focus=19665#Comment_19665 Wed, 30 Apr 2008 10:12:43 +0100 Ads
SimonH, is £880 + VAT a good price for a 280 litre store and if so could you tell me where you saw it please.

Dantez, as far as I can see the options for being able to provide mains pressure water are, as you point out, an unvented cylinder or a thermal store (I'm excluding pumps). So, what are the pros and cons - aren't unvented systems about the same price as a thermal store? And over time might not a thermal store be simpler and less costly to maintain? I am not an advocate of any particular system, but personally prefer the simple to the complex.]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=1649&Focus=19728#Comment_19728 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=1649&Focus=19728#Comment_19728 Wed, 30 Apr 2008 20:57:50 +0100 SimonH
If you go for unvented then the heating system will be on a split off from the main boiler flow circuit. The water in the tank is what goes to the taps. The coil that comes from the boiler split is on the same circuit as the rads.

In a store the tank water is shared between the rads, whilst the incoming fresh water goes through the coil.

The other key advantage as already mentioned, is that when you boiler does fire, it can keep going until the store temperature reaches say 80 degrees and then cuts out. This means that when the central heating is on, instead of firing say every 15 minutes, the store will buffer the heat and means it might fire only every 30-45 minutes. This is important as starting up and stopping a boiler is when it is least efficient. I'm guessing you need a decent programmer that's aware you have solar, so it doesn't fire the boiler at 5am on a summer morning, just as the sun is about to come out !

I should have checked my figures, it was £990+VAT but that' still good. It's for an Aqua-Sol store from a company called Underfloor Direct based in Northern Ireland. They were at the home building an renovating show, so it might be a special show price, but I'm sure you can twist their arm. Contact number is 028 9263 4068. info@underfloordirect.co.uk. Their website doesn't show it, but looking at the picture I have on the brochure I've found the same product here...

http://www.halosolar.com/products_cylinders.htm
http://www.rayotec.com/water_underfloor_heating/solar_linked_underfloor_heating/index.html

Simon]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=1649&Focus=19732#Comment_19732 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=1649&Focus=19732#Comment_19732 Wed, 30 Apr 2008 21:30:30 +0100 Dantenz https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=1649&Focus=19801#Comment_19801 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=1649&Focus=19801#Comment_19801 Thu, 01 May 2008 21:43:31 +0100 paul&gyn Here in France the usual arrangement is a sealed hot water cylinder, heated by off-peak electricity. Anyone with half a brain can fit them, they come as standard with a 'groupe de securitie' which is a combined cold fill, stop-cock, drain, and 3-bar pressure relief valve. Hang it on the wall, connect it up, and away you go. My 200 L unit cost under 200 Euros including a tripod for it to sit on.
Admittedly, once you start to add a CH coil the euros start to add up, but even so....

p]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=1649&Focus=19817#Comment_19817 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=1649&Focus=19817#Comment_19817 Fri, 02 May 2008 09:31:28 +0100 Tuna https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=1649&Focus=19937#Comment_19937 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=1649&Focus=19937#Comment_19937 Sun, 04 May 2008 09:54:10 +0100 PDobson
http://www.navitron.org.uk/e107_plugins/wrap/wrap.php?13]]>