Multi Fuel Stove

[stu1753]

Hi to all who look at this problem.
I currently have a gas boiler (heat only) for both central heating and domestichot water. The boiler feeds directly to a 'Flowmax Thermal Store' 180 litrevented cylinder with integral feed and expansion tank. The hot water is servedat mains pressure (4 bar) via a coil within the tank which incorprates ablender and has been working ok for circa 18 years. The CH and DHW arecontrolled via a three port diverter valve. There are 12 radiators in the houseat present two of which are open all the time to allow for pump overrun whenthe boiler switches off. The remaining radiators have thermostatic valvesfitted.

With the increasing cost of gas I amthinking of opening up an old chimney within our sitting room and if it is ok,will install a multi-fuel burning stove with a back boiler to provide heat forthe room and excess to feed directly to the thermal store cylinder in my loft.

I would like to install as big astove as I can to feed surplus heat to the store and then pump the waterthrough the central heating system. I would install an additional pump for thispurpose which would be totally independant of the existing system and would becontrolled by a high level stat set at 80 deg to bring the pump on and offwhen the temperature falls. The gas system would never be run in tandem withthe stove at any time for safety reasons.

I am aware of the problem associatedwith loss of power to the pump which will increase the temperature of thecylinder to a dangerous level. The integral F&E tank would cater in theshort term for expansion but woould it be necessary to fit a bypass on thestore pump to cater for this event?
I have also been advised there is aGerman made stove on the market which has a 'wax' type of plug which is fittedon the stove drain point and melts somewher around 90-95deg thereforethe cylinder water would be safely drained to the outside. Does anyonehave knowledge of this?

I have attached a layout drawing ofboth the existing and proposed systems (excluding the controls) and would beobliged if anyone could offer advice oin whether the layout shown would sufficeor what alterations etc would be required.

Thanks in anticipation for anyonewho replies.

 

[snowhead]

Question, Who is doing the final design / install?
Answer, A HETAS approved installer.

 

[lame plumber]

you main issue is the fact you want a big a stove as possible etc etc, which is ok if your not going to using the room its placed in as it will be intolerable in that room once the stove is working at full bore. Its not as simple as enough heat to warm the room and the rest will warm the water!!!!!!!!!!!!!!!!!!!!!!

 

[Centralheatking]

As above this system will have to be designed and signed off by a hetas person - no question.

Big (and little) solid fuel and wood burners are essentially uncontrolled appliances - you cannot just
switch them off and can become very explosive as water expands 200x + its original volume when
turned to steam.

In the old days a back boiler etc was connected to cylinder via lge dia pipes and was unpowered using natural convection - hooking your idea up to a fully pumped system will need careful thought esp
if the power goes off when the thing is going full tilt !.

centralheatking