wood burner and back boiler

[aitch]

I'm in the market for a wood burning stove and am considering having a back boiler as well to give hot water and heat for 7 radiators.

 

I have been talked out of it previously by a couple of people, one saying my room (5.6x3.6m) is too small for one and another saying that once the hot water is up to temperature his stove struggles because of the change in air flow(?) and not to bother unless I had a huge tank (only room for a standard).

 

I've taken the gas fire out and part of the fire place and found some disconnected pipes for an old back boiler so I've been considering it again.

 

What are your thoughts on them? Worth investing in one? I'll have to buy most of my wood so it's not free heat.

[detritus21]

We have one that does 7 radiators 5 of which are doubles. We burn both wood and coal. Just burning coal over winter we can spend around 80 quid a month but that is 24/7 burning with around 80% of that time the rads on. We have a standard cylinder and our rooms ain't massive. As it was a bit cold today I have gone overboard and am sat in shorts and t-shirt and am too hot. We have burnt 2 buckets of coal and three logs all day. If I had a gas boiler i'd dread to think what I would spend on gas. Its not as easy as gas as its not instant. It takes a bit of playing with to get right. Would I go back to gas not a chance. Just burning wood ain;t going to be cheap. Get a multifuel and burn some coal as well.

[detritus21]

The other alternative is get one without a boiler and have it as a room heater. We have one in the front and its about 7kw. It warms the room well and is more akin to having a gas fire but much nicer.

[skyhuck]

I heat our large home with wood, but my wood is free from my tree work business, I don't think it would be viable if I was buying my timber in.

[Perkins]

A stove designed specifically for heating water, such as the stratford eco20, is thermostatically controlled, meaning the air intake opens as the water temperature drops, and vice versa.

 

For this reason, when the water is 'up to temperature', the stove throttles itself down, and your fire will slumber. This is the problem I think you have been advised of. However, it is only a problem if the stove room isn't warm enough, and you don't have a heat loss from the water circuit.

 

The solution is to have a heat loss, such as your radiator circuit, controlled by a circulating pump. It is also important with modern efficient stoves to have a radiator in the same room as the woodburner, because so much heat is transferred to the water jacket, that the stove room can remain cold.

 

Normally, you would have water circulating by gravity to your indirect hot water cylinder, and via a pump to your radiators. When the pump is on, you get a warm house, and when the pump is off, you get heat transferred to your cylinder.

 

A thermostat near the bottom of the cylinder is a good idea, used to switch on your circulating pump if the water at the bottom of the tank is up to about 65degrees.

Edited October 12, 2013 by Perkins

[Lorn Logs]

Mine here is a 12 kw Coseyfire I got of the tinternet...we had an old open fire with a wraparound boiler, took the fireplace and old boiler out and connected the stove to the old inlet and outlets got my mate a plumber to do the pies and check it all, I run 4/5 Ra and a tall towel rail off it and it heats the house...in fact it's roasting here even on the coldest days. Best thing I ever did.

[w6cloggs]

19 years ago we fitted a clearview stove with wrap around boiler, it is running 5 radiators and doing the hot water.

It is in 24/7 all winter burning only wood a builders barrow with as much as you can get on it will last about 24 hrs.

we also had the flat top one so there is a lot of one pot cooking that looks after it's self all day long.

It in no problem to keep it in but by shutting it down it runs a bit cooler than is good for the chimney so it has to be swept twice a winter

[peatff]

My wife found the receipt for our stove the other day, we've had it nearly 13 years. It's a Hunter Hawk rated at 4kw on coal and 5kw on seasoned wood. It replaced a seldom used gas fire and has been lit tonight and gives a good amount of heat for it's size.

[Pumpy]

I fitted a Herald Hunter Multi-fuel (27kw) some yrs back, it heats two bedrooms, a bathroom, and DHW. I have run it on wood and coal.

 

If you need it to run 7 radiators, you'll need to know the size of the rooms, windows, and insulation for the btu calculations, might be best popping into a decent stove shop with some numbers to give you a good idea what size stove you require, then you can look at different models that will do the job. I doubt the existing back boiler pipework will be sufficient it'll be a big install for central heating too, and a right headache if you want to connect in another boiler, say your current one.

 

Think about the availability of logs in a bad winter. If you are buying wood in, you will need a HUGE woodstore, big enough to get you through the winter, a double garage size woodstore would be my minimum. Otherwise, say you need to re-supply mid winter, you pay top dollar and that's IF anyone has any dry wood to sell, if you end up only being able to find high moisture content logs, you'll freeze. If you use coal instead (and that will be the only way you'll keep it in all night unless you have a lot of real dense wood) it'll use about 18kg a day minimum if it's on 24/7, coal is about £10 per 25kg bag, or maybe a bit cheaper loose.

 

Unless you have a plentiful supply of cheap, or free wood, and a very big logstore, I'd say you'd be better off on mains gas central heating, with a smaller logburner in one room if you really really want one.

 

HTH.

 

Edit: Oh and think about how your DHW will be heated in Summer, do you really want to light the logburner in Summer, or leave it to the immersion heater at about £200 per month?

Edited October 13, 2013 by Pumpy

[skyhuck]

 

Edit: Oh and think about how your DHW will be heated in Summer, do you really want to light the logburner in Summer, or leave it to the immersion heater at about £200 per month?

 

That can't be right, we leave our immersion heater on all summer (may to october, this year) we have 4 big plasma and LCD TV's, plus running a swimming pool filtration system, plus my 4 children like leaving lights etc on and our electric bills are about £200 per month.