DHW conversion to heat store

[Doobs Too]

Hello,

My first post on here so please excuse lack of jargon, wrong terms etc. I'm a DIY'er not a real plumber, that's my excuse anyway!

I've just moved into an old house with a vented un pumped hot water system. I'm looking to convert to mains pressure hot water and don't want the expence / hassel of going unvented so thought a heat store would be the way to go. My question is can I use the old Ideal Standard (E type RS it says on the inside of the case) boiler to run a heat store with appropriate control upgrades?

I guess I'll need a pump, anything else? Will a normal programable timer run it OK?

If so, any tips on where to get a cylinder? Cursory looks on t'internet have not been too illuminating. I'm at the begining of my research though. Is it just a case of piping up a normal cylinder the other way around (i.e. boiler into the big bit, mains water to the coil)?

Any other thoughts / suggestions greatly appreciated. I'd like to be complete before it gets cold and cost is an issue hence not ordering a new boiler and Heatray (spelling??) cylinder straight away.

Thanks,

Alastair

Further to my original post, I have a leak in the vent pipe of my antiquated system. The boss wanted a bath this evening so I closed the gate valve to the HW cylinder and ran a little water off with the HW tap to keep the level below that of the leak (approx 1st fllor cieling level). This stopped the leak but kept the cylinder full of hot water.

When it came to running her bath I thought I'd open the gate valve, put the tap on and run a bath. Once full repete the proceedure of closing the valve, and running off a bit of water then turn the boiler off for the night. This has worked but a curious effect is before I turn the gate valve ON to run the bath, hot water comes out of the cold water tap (mixer bath tap). How is this possible? I thought if the gate vales is shut more cold water can enter the cylinder to displace the hot water run off, therefore no hot water?

Sorry for the epically long posts.

Alastair.

 

[MarkB]

Hello Alastair,

Unfortunately you can't just pipe up a regular cylinder back-to-front as you suggest.

The coils within a thermal store are usually higher efficiency (or a plate heat exchanger) and also have to be pressure rated. Thermal stores also tend to be run at higher temperatures than a standard vented cylinder so a blending valve must be used to limit the resulting hot water temperature.

Try looking at Gledhill and Albion for starters (these are the ones I have come accross) but there are quite a few manufacturers of thermal stores.

Mark

 

[Doobs Too]

Thanks for your reply Mark, I'll start with those two and see where I get.

Will normal boilers run heat stores? I'm trying to work out if I can replace the boiler later rather then do both (cylinder and boiler) at once. It's a question of cost.

Alastair.

 

[Bob Croft]

You will need to convert your system to fully pumped and add appropriate valves / thermostats & programmer to control your CH and DHW cylinder. As already noted thermal stores tend to store water at a higher temperature than a conventional cylinder so you will need to run the boiler at a higher temperature. Although you do not need to be registered to install thermal stores in my opininon it is not a job for a DIY person. I would advise you to use the services of an experienced installer who can advise on the best set up, suitability of your boiler and suggest an upgrade path to bring the entire system up to the most efficient spec. over time.

 

[Bernie2]

Hi Alastair!

If your determine to do it yourself, whilst its a bit involved its not hard, if you plan it properly and take all the precautions against scalding water.

Many of the sites also offer installation instructions, and providing you follow those and can do the physical things such as soldering and bending pipe it should be within a competent DIYer's abilities.

 

[Doobs Too]

Thanks for the info gents, much appreciated. I can join and bend pipe so I think I'll give this a go at some point. Just got to find something for sale, unvented seems to be much more easlily available.