Recommendations for thermal store?

[sirocosm]

I am looking for a thermal store. Preferably a 300l stainless tank with one large DHW coil (~4 sq m). I would like something like this:
http://plumbingsupplies24.co.uk/hygienic-buffer-storage-tank-vertical/

but it is a mild steel tank. I don't think I can find a G3 to commission it for me, so I'll probably have to install a vented system, so I am looking for something similar in stainless. All the ones I have seen online have rather small DHW coils, which means high store temperatures.

Cheers,
Richard

 

[ianmcd]

You do not need a G3 engineer for a thermal store

 

[Ryler]

grant do stainless steel though not sure about dhw

 

[sirocosm]

You do not need a G3 engineer for a thermal store

I have read that you need G3 if it is a sealed system, although there seems to be some debate about that.

 

[oldbutnotdead]

If you're burning solid fuel you don't want a sealed system. Re DHW, have you thought about plate heat exchangers- mains pressure hot water without pressurised system.

 

[bernardgreen]

DHW at mains pressure can be achieved using a coil inside the heat storing cylinder.

A plate exchanger requires electical power and controls to pump water from the store through the exchanger. No power = no hot water.

 

[sirocosm]

If you're burning solid fuel you don't want a sealed system. Re DHW, have you thought about plate heat exchangers- mains pressure hot water without pressurised system.

I was just going to use a gas boiler.

All the cylinders I can find with a decent sized coil (> 3 sq m) are made from mild steel. I may have to go plate exchanger route, even though it is more complex. It seems it is difficult to find a G3 plumber just to commission the tank. (I am in Norwich).

 

[speccy]

Really think hard about using a Thermal store. Ours is unvented but has been a fking absolutely bain of our life, it was installed by an utter cowboy. It needs to stay near 80 degrees and has a narrow operating range so if drops below say 55 degrees you lose decent hot water. Most experienced engineers ive spoken to have mentioned huge tanks double or more our measly 210 litre tank.

I wish we had gone for a unvented cylinder but then we are trying to use a solid fuel burner with ours which needs to be right or apparently it will blow our house up!

 

[speccy]

If you're burning solid fuel you don't want a sealed system. Re DHW, have you thought about plate heat exchangers- mains pressure hot water without pressurised system.

Have you seen this system though http://www.h2panel.co.uk/ a very helpful chap says this works with a solid fuel and unvented system. When you say don't want are you referring to the risks or is there a detailed requirement of safety systems in place before sign off? We were looking at an unvented conversion and getting rid of TS but it's hard to get a response from anyone on how we may safely do it.

 

[oldbutnotdead]

Have you seen this system though http://www.h2panel.co.uk/ a very helpful chap says this works with a solid fuel and unvented system. When you say don't want are you referring to the risks or is there a detailed requirement of safety systems in place before sign off? We were looking at an unvented conversion and getting rid of TS but it's hard to get a response from anyone on how we may safely do it.

The latter- a properly designed and installed open vent system can overheat and boil up quite safely- yes it'll be noisy but that's it. Pressurised systems are not DIY & pressurised with solid fuel definitely not DIY. You'll have to talk to some real qualified engineers (and probably spend some real money) to fulfil your requirements

 

[sirocosm]

Really think hard about using a Thermal store. Ours is unvented but has been a fking absolutely bain of our life, it was installed by an utter cowboy. It needs to stay near 80 degrees and has a narrow operating range so if drops below say 55 degrees you lose decent hot water. Most experienced engineers ive spoken to have mentioned huge tanks double or more our measly 210 litre tank.

I wish we had gone for a unvented cylinder but then we are trying to use a solid fuel burner with ours which needs to be right or apparently it will blow our house up!

One reason for this is that the DHW heat exchangers are too small. I had a thermal store in a previous house and I used to run it at 60C. It was 300l, and had a DHW exchanger size of 4.1 sq m. Most are less than half that size. It also depends a bit on your boiler size. You can use a larger boiler with a thermal store.

 

[snb]

Gledhill produce a stainless steel heat pump thermal store. This has a much larger heat coil for hot water production at store temp of 60c

 

[Ryler]

If I was fitting an unvented cylinder unto my own solid fuel system I'd just fit a twin coil solar cylinder and use the Danfoss RAV1 (KOVM)

Which I currently use on my vented cylinder. It works without auxillary energy and is therefore much safer than electric controls. So in a power cut, the cylinder still heats and is still shut off.
The H2 is £600 plus the cost of fitting which is expensive. Granted, it caters for two boilers.
The Ravi (KOVM) ranges from £150 - £240 online. Plus fitting which is fairly simple.

 

[sirocosm]

This store can be had for just over £600 with insulation and it can be had with a whopping 6.3sq m stainless DHW exchanger, although it is mild steel, so it would need to be on a sealed system.

https://buffer-tank.co.uk/lmt-buffer-tank.php

Has anyone any experience with this company?

 

[Ryler]

Has anyone any experience with this company?

Sorry no. That looks way too industrial for a domestic property.
Just re read this thread. You want to heat a thermal store with a gas boiler?
Just fit an unvented cylinder.