Hot water storage for a combi boiler

[james10622000]

Does anyone have any experience providing hot water storage in a combi system, I want to have my combi boiler feeding a hot water storage tank, if possible I would also like to have a wood burning stove heating my tank as well.
I want to do this for 2 reasons: To reduce my gas bill from £150 per month to £50 (hopefully) and the combi system takes forever to fill a bath.
Any information would be gratefully received.

Thanks

James

 

[Hugh Jaleak]

Can be done, the cylinder coil tees into the heating output from the combi, using a 3 port valve to share the flow between cylinder and existing rad circuit. Will need wiring up to allow the combi to fire the heating circuit whenever the cylinder stat and/or roomstat call for heat and operate the motorised valve to suit demand. Combi HW output can be used for kitchen sink, dont use vast amounts of HW there, feed bathrooms from the cylinder.

Solid fuel is another matter, as you have no thermostatic control over it. I think you need to have a heatsink somewhere on the water circuit to dissipate heat from the stove when the cylinder is hot. Usually a radiator connected into the circuit.

 

[holty]

you would proberbly be looking at a vented twin coil cylinder. cos the solid fuel stove cannot be on sealed system.not gonna be a cheap setup thats for sure.

 

[dextrous]

Is a woodburnign stove that efficient? Honest question.

Also, are there multi-coil cylinders on the market to allow for a variety of heat sources (eg the two mentioned, plus ground source heat, solar panel, air heat exchangers etc etc)? If not, then why not

 

[james10622000]

Not that efficient Dextrous, but that does not concern me , I will get the wood for next to nothing and don't mind chopping too much.

 

[Agile]

Cylinders become extra expensive when two coils are fitted as the makers cash in on people with too much money who want to install solar which has no recovery financially.

A simple cheap solution is to use two standard cylinders in series with the first preheated by the wood stove.

But as suggested the wood stove must be on a vented system with a heat sink able to dissipate ALL the heat which would be produced from a fully charged wood stove if the electricity failed.

To avoid the water getting too hot a Cyltrol thermostatic valve could be used to close the input to the wood heating coil leaving the heat sink rads to dissapate the heat.

The problem is that its difficult to design a fail safe system which puts the heat into the water store without wasting heat on the heat sink.

Tony

 

[james10622000]

Thanks Agile, I have checked the prices and this is substantially cheaper than a twin coil system, does anyone have any experience of using both a Combi boiler and an additional heat source (i.e. a stove boiler) in the same system?

James

 

[John67]

The easiest way to use a combi is to leave one tap remaining on the boiler .

I would recommend a thermal store cylinder ( Gledhill torrent RE is one of the cheeper ones ) Which as long as your mains water pressure is ok will give you mains pressure hot water