Combining a wood burner with lpg boiler - ideas?

[JasonLR]

hi, I’m new to the forum. I’m looking for any advice on best way to connect a wood burner with back boiler that will provide heating and hot water when the lpg boiler is switched off, yet if you can’t be bothered burning wood in the wood burner you can switch the lpg boiler on for instance heat and hot water. I’ve already concluded there will be 2 part heating on rads, 1 set of rads on the lpg boiler and another set of rads on the wood burner - although I’m open to other ideas on this. I’ve attached the design I’ve done using a thermal store tank, any comments, ideas would be appreciated, thanks

 

[ShaunCorbs]

H2 panel

 

[snowhead]

H2 panel

And a HETAS engineer

 

[JasonLR]

Thanks, the H2 Panel looks interesting, the only thing that puts me off is that it uses electric to run. The house is off grid so I’m trying to find solutions that don’t consume power. Is there a way of measuring which works best, heat exchange v’s H2 Panel ?
Yes, I’ll need hetas engineer, also a lpg boiler guy - am I looking to get 2 different trades in for this or are some hetas and lpg approved. I’d rather find 1 guy who can do all

 

[ShaunCorbs]

Might be worth asking the h2 guys can they design something

 

[king of pipes]

Have a look at the Dunsley Neutralizer but as said above a Hetas and LPG Approved installer will be needed . cheers kop

 

[SimonG]

Your design doesn't cut it. It's unsafe.

You need an engineer who's competent and experienced.

H2 panel defaults safe in event of power failure.

 

[JasonLR]

Why it is unsafe ? If you are referring to the pump and power failed it reverts to gravity fed. I don’t think the pump is necessary anyway, was just a precaution

 

[Best]

Why is the pump shown on the drawing, fitted on the gravity pipes of the wood burner?
It shouldn't be there and not needed anyhow on a circuit that can work on gravity.
It is the output from thermal store that is also important and requires a pump.
The solid fuel also needs somewhere to dump excess heat for in the event of power failure etc.
No point in you getting too in depth with the design, other than to help you direct an installer to design it their final choosen safe and satisfactory method.

 

[JasonLR]

everyone I’ve approached so far have come up with systems that zap electric, the house is off grid which I don’t think many have had experience of. So before I continue enquiring with the hetas, lpg guys I’m trying to get a better understanding of how these systems work and yes, I am trying to design the system but only so I can go to them and say I want something like this, just 1 pump, nothing fancy that zaps electric. I get your point on the pump, this needs to go on the output to the rads and it needs a heat link rad straight from the burner.

 

[SimonG]

There's no need to reinvent the wheel. Systems exist already that are proven and safe.

 

[Best]

Pumps don’t use much electricity and nothing beats their ability to push heat around radiators.
However, if a log burner is installed on a floor level below rads, then carefully installed gravity circuits will work well.
A failing open zone valve is also a possibility

 

[Plumbagain.]

Old house gravity heating....
Gravity hot-water heating | Old House Web

No electric needed.
But if you are off grid, how will you power the lpg boiler?

 

[Best]

I actually like the simplicity of a gravity system. Makes sense on a solid fuel system on a compact house, so that you have heat even in a power cut.
The flow will constantly put air into radiators if pipes are wrongly teed off from primary flow pipe vertically.