Rads off a back boiler

[jimbo86]

Hi. I was wondering if anyone could have a look and see if this would work.
Firstly i am not a plumber. I am a NIC electrician
I am renovating a house in France and am trying to sort some form of heating. The village doesn't have a gas supply, there is no room for an oil tank. The house is fairly small spaces. There are 3 floors and a basement each 15m square. it is a 2.5m wide terrace house, so not a lot of external walls, and roof is being redone, insulated with triso super 10 (equivalent to 150mm celotex) and also rock wool flexi slab.
I have attached a plan of what i would like to do.
A woodburner with back boiler in sitting room, running 3 different circuits. woodburner is 4kw to room and 5kw to boiler

Circuit 1: 3 radiators, all on floors above the wood burner. with the one to the bedroom having a 2 port valve connected to a room stat, so it should turn off first. leaving 2 constantly on. would like this run through thermosyphon if possible. want this as the primary circuit to warm house, hot water can be heated by immersion if necessary.

Circuit 2: opens a 2 port valve to hot water tank, opened when the return pipe reaches say 50 degrees (what is used for this? i see some cylinder stats can clip on pipes, but would this only work the wrong way i.e. cutting out at the temperature?) would like this on thermosython as well. if possible.

Circuit 3: a pump will be needed here. another 2 port valve that opens the same as above, but when the temperature of the return is higher, say 60. To run a radiator in the basement. so pump would start when the 2 port valve opens. would have this circuit, mainly to use any excess heat if there is any to put a bit of heat into basement to try and keep it dry. doesn't matter if it's not on that much. would it even get hot at all?

would it be worth putting circuits 1 and 2 together or would it take to much heat from the rads?

sorry this is so long.
any help on this is much appreciated.
thanks

 

[lame plumber]

get in a french heating engineer, their rules probably arent the same as ours!

 

[iain85]

What size wood burner are you planning on using?
where is your header tank? Or are you thinking of using a sealed system? (only some stoves are designed for this)

 

[jimbo86]

there isn't a problem with using a back boiler to heat water/ radiators here, i know other people who have it, i'm just not sure if my layout is possible. others seem to have it supplying hot water, and having 1 heat leak radiator.
I am using a woodburner that has outputs of 4kw to room and 5kw to the boiler.
the header tank will be above the hot water tank in the cupboard, or could be put high up on the floor above if this is better. does it need to be above the highest radiator?
I looked into thermal stores, but the cost comes into it then.
I am putting in some thin 400w electric radiators as well, in case of cant be bothered to light fire.
thank you

 

[AWheating]

the bigest safety concern you have is that there must be somewhere for the heat to go in the event of a power failure. So you must have a gravity circulation path. Which would normally be the hot water cylinder/ FandE tank.

this is because you cant turn a fire up and down like a gas appliance. Speak to local engineers about whats normally done.