Wood burner/ electric boiler

Right then!

I am in the process of hacking my central heating about, did have a vintage oil boiler but have decided to go green and get a log burner with back boiler (rated at 9kw to room and 9kw to water) the existing system has a 28mm gravity dhw circuit which is fine and a 28mm vented heating circuit,

I plan on incorporating a 9kw electric boiler to boost in the morning when the fires gone low overnight however they are all 22mm and I am unsure if it would be fine to simply plumb it into the flow side of the back boiler incorporating the existing pump or should I go across the flow and return and fit another pump?

Anythoughts?!? i'm sure it wil work either way but want to make it as good as poss!

See attached image [/img]

If your electric boiler is heating radiators only, well all you'll need is to tee into your existing CH F&R & fit a NRV after the solid fuel circulator & add a circulator for the leccy boiler & have a NRV after it. Of course you'll need an open vent on your leccy boiler also.

I think I know what your trying to do. If I'm along your line of thinking it has been done before.

Have a look here for the details http://www.dunsleyheat.co.uk/boosterheater.htm

Simples

HTH

Dan

<edit> Cos I'm thinking of adding one to my solid fuel heating system</edit>

If you connect in-line like that you'll be heating up the back boiler also, that's the last thing you want to do.

adrok said:

Right then!

I am in the process of hacking my central heating about, did have a vintage oil boiler but have decided to go green and get a log burner with back boiler (rated at 9kw to room and 9kw to water) the existing system has a 28mm gravity dhw circuit which is fine and a 28mm vented heating circuit,

I plan on incorporating a 9kw electric boiler to boost in the morning when the fires gone low overnight however they are all 22mm and I am unsure if it would be fine to simply plumb it into the flow side of the back boiler incorporating the existing pump or should I go across the flow and return and fit another pump?

Anythoughts?!? i'm sure it wil work either way but want to make it as good as poss!

See attached image [/img]

Untitled

• adrok
• 13 Sep 2010
• 1

Click to expand...

A woodburner has no boiler controls as such apart from your air inlets, if left unattended it can overfire.
If hot water is flowing into your header tank it is more than likely your pump had failed.

Lochy said:

If you connect in-line like that you'll be heating up the back boiler also, that's the last thing you want to do.

Click to expand...

Hiya,
I thought they are designed to boost the water temp when the fire is low, and turn off once you've got more fuel on.

True I wouldn't want to use it if I was not going to light the fire......

Thinking about it though I've not had a problem with my heating being all run by coal, and it is still warm enough in the morning. Maybe it is a bit pointless

I would have thought the OP was wanting to use it on C/H only until his stove got going. Which is easy enough to do and he can stick in a relay to turn the leccy boiler & circulator off, when his WB stove Hi/Lo stats pull on the WB circulator.

You are fitting a Hi/Lo stat???

Over the winter period you can save a lot of money on fuel costs with a woodburner, just a few pointers tho, a woodburner is labour intensive in cutting your logs to size, you need a good source of supply (a friendly tree surgeon) forget cutting up with a bow saw, too slow you need a chainsaw and a good log bench.
Your logs must be dry, 16 or 17% moisture content otherwise you will be producing steam and resin which can penetrate you chimney breast if you dont have a flue liner.
Two essential gizmo's are a digital moisture meter costing about 20 quid from Machine Mart and a flue temperature thermometer mounted on the flue pipe just above the stove, this will tell you if you are firing economically, too low and you are producing resin, too high and you are overfiring and risk burning out your bars, it also shows you the correct temp for burning.

Eh? What? You don't need all that. With a little experience a stove user can usually work out what's going on.

Unseasoned wood will smell green, will hiss and steam and bubble at the ends and burn sluggishly.

Seasoned wood will burn bright and clean and will ring if you knock two pieces together.

Too much oxygen and your stove will drive you to the corners of the room with knotted hankies on your heads and cocktails in glasses with little umbrellas.

Too little oxygen or burning evergreen rather than hardwood will produce a sluggish, smokey yellow flame and a lot of tars on the glass.

The right amount of oxygen in the right place will give you a clean, glowing base of embers with flourescent flames licking gently around the logs and a clean glass with clear atmosphere above the fire.

Correct storage of the wood is essential - you need a sheltered stack preferably in an airy place with the wood on old pallets. Don't accept lots of dross, lots of beaten-up lightweight pine or lots of resinous woods like cypress. Get hardwoods like oak, ash, beech, well dried sycamore and so on. Birch is excellent. A hand-chopping axe helps for the big bits and a small Ryobi or similar chainsaw is invaluable if neighbours are in the habit of dumping trees on your doorstep! Obviously the chainsaw comes with protective gear and very great care and attention to the job in hand.