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Wood fired central heating without electric

(40 Posts)
Katymac Mon 09-Nov-15 15:21:45

I have a wood burner that fires out central heating

It has an electric pump

If the electric is off (longer term) is it safe to use my wood burner?

howtorebuild Mon 09-Nov-15 15:35:02

I was going to look into pricing up a woodburner. What is the benefit over an open fire?

Stratter5 Mon 09-Nov-15 16:28:33

Cleaner and higher heat output from less fuel. Chimney liners are bastard expensive though.

I don't think so. Our wood fired system has a backup battery for this reason. I think they auto shut down if electricity goes off don't they?

atticusclaw2 Mon 09-Nov-15 17:10:43

I don't think it will work. We have a log gasification boiler attached to an accumulator tank. The furnace could be lit but it wouldn't then heat the water in the tank and the central heating controls wouldn't work.

You'd need a small solar panel.

Katymac Mon 09-Nov-15 18:25:59

Well I can't see it shutting down as I can just keep on shoving on logs wink

It's gravity feed for the overflow radiator (I think - that could be nonsence)

I'd better ring the manufacturer

winchester1 Mon 09-Nov-15 18:38:24

They aren't normally safe to use without the leccy on.

queenrollo Tue 10-Nov-15 16:07:09

It depends what system you have. Our heating is from the Rayburn and we have a gravity fed system. We actually lost power the other week for 4 hours and having checked with our installation engineer we can keep ours ticking over, but advised not to fire it up too hot. Our pump is designed to boost the water round the system if it goes over a certain temp.

Sadik Tue 10-Nov-15 18:20:34

Agree you'd def. need to check, probably with the plumber who installed it. We've also got a wood fired rayburn based system and it's fine running it gently without the pump as it thermosyphons (sp?) round the upstairs radiators reasonably well.

atticusclaw2 Tue 10-Nov-15 18:38:52

Agreed. Our system is very different. Our heating and hot water runs from a log furnace in the garage.

Atomik Tue 10-Nov-15 18:48:53

I have a very old "runs the central heating" fireplace. If the pump conks out the water stays in the fire bit, getting hotter and hotter, turning to steam and then <<<boom!>>>> !

So to avoid the explosion issue there is a pipe that runs from the back of the fire, through the under th stairs cupboard and it pokes out into the back garden, where the over hot water can disperse before it damages the system.

That's the theory anyway. It's never been tested.

I believe newer versions have some sort of "vase" up in the loft, or tucked under the stairs, that let the water cool in case of power outage that stops circulation and leads to overheating in the actual insert.

PigletJohn Wed 11-Nov-15 12:38:55

without the pump, there will be no circulation to take the heat away, so the water will overheat.

You will (should) have at least one radiator that cannot be turned off, it will be upstairs, so that convection can take away excess heat if this happens. However, if it does, you are supposed to damp down the fire and stop feeding it, so the radiator can cope until the fire goes out and you get the problem fixed. Otherwise the water might boil with undesirable effects. It is possible to design the whole system to run on convection, but it will not be very efficient. It was the norm until the 1960's.

Central heating (including boilers) doesn't use much electricity, usually less than 3Amps, and some people have the boiler supply on a plug and socket so they can put a stand-by batter-powered inverter on during a power cut. You mustn't use a petrol generator indoors.

cozietoesie Wed 11-Nov-15 13:02:10

...with undesirable effects...

That sounds like an understatement and a half! grin

Katymac Wed 11-Nov-15 13:57:17

Thanks everyone

some people have the boiler supply on a plug and socket so they can put a stand-by batter-powered inverter on during a power cut

Can you explain that a bit more?

PigletJohn Wed 11-Nov-15 16:41:38

boilers are most often connected to the electricity with a Fused Connection Unit

But (slightly less neatly) can be done just as well with a plug and socket

A 3Amp fuse in the plug is pretty sure to be correct.

In the event of a power cut you can take the plug out of the wall socket and put it into the battery-powered inverter

Katymac Wed 11-Nov-15 17:18:13

That is the pump & there is a double socket in the airing cupboard so I guess the white cable is the power lead

So I think I know a man who can change it to a plug and I can plug it in

Any idea how much an inverter would cost> the prices on that page seem to veer from ridiculous to completely silly

I guess a car battery would do the job? or would I need something more substantial?

Katymac Wed 11-Nov-15 17:38:02

This is the pump

grumpyoldgitagain Wed 11-Nov-15 18:14:14

A car battery would work but a high amp leisure battery would last better

Invertors start at around £30 for a 150 watt model but you will need to know what the power requirements of the pump are to know what size invertor you need

PigletJohn Wed 11-Nov-15 19:27:23

you should not feed the pump itself. It will be controlled by at least a thermostat. You need to find where the heating system is connected, and feed it there. Whoever services the stove or boiler could do it (they need to be able to isolate power to the whole system before doing maintenance).

PigletJohn Wed 11-Nov-15 19:30:41

btw, a deep-discharge battery as used for golf carts, wheelchairs, boats, fork-lift trucks and caravans is more suitable, but they are sold in low volumes and are considerably dearer than car batteries.

Katymac Wed 11-Nov-15 20:16:31

This is achievable

Also I can do it a bit at a time as I can afford it so I can get a plug put on then when I've saved up again I can buy the battery & presumably a way to charge it

Of course ideally I'd have done it in the spring so it was sorted for now- but I'll see if I can get it sorted now

Not having electric is bad
Not having heating is dealable with (go to parents)

But knowing I could have sorted it out would be frustrating

PigletJohn Wed 11-Nov-15 20:25:20

my boiler just started up, and according to the Owl, power usage increased by about 180Watts.

However the boiler fan (30W) was about half speed, and the pump (mine is an energy-saving Alpha) may only have been running at about half power, I can't tell. Yours will vary according to size, age and efficiency.

I think you would do better to get a 300W or greater one. It should be able to run your fridge-freezer as well (possibly not both at the same time). It might be more important for you to keep the food fresh.

At the moment the whole house is only using about 500W, thanks to energy-saving lights and modern fridge-freezers. However that would probably run a car battery flat in an hour, so you would have to ration your heating.

Katymac Wed 11-Nov-15 20:34:37

No boiler so it's tricky - I think our pump is on all year the guy that fitted it suggested it because it was less likely to seize up

Our electric bill is obscene....but I do have some electric underfloor heating (which hasn't been on yet this year)

Freezer would be exciting (I have 3) but I think warm over night is more important atm; so maybe that's for next year

grumpyoldgitagain Wed 11-Nov-15 21:15:19

Reading some of the replys I think people may be misunderstanding your system

If it is anything like ours it is a wood burner with back boiler which will gravity circulate to one radiator as a minimum to allow heat dissipation and the system is circulated properly by a pump around all radiators

No electric is needed at all as long as it is kept on a low burn as the gravity fed radiator will get hot and natural thermal circulation will do the job

We then have a heating pump for circulation controlled by a pipe thermostat on a pipe leading out of the boiler, no other thermostats anywhere

The only thing I would need to power off a battery and invertor is the pump and pipe stat, the pump I have is only 40 watts so a fairly small invertor (approx 50 to 100watts) should do it without a problem

Katymac Wed 11-Nov-15 21:20:51

Yes it will do 3-5 on gravity but because of the layout we have 6 so they popped the pump in

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