Struggling to get our stove upto temperature

[Piggywiggy38]

Hi,

We recently bought a 5kw multifuel stove and have been burning kiln dried logs with success, but they don't last long we are trying to move onto smokeless coal.

We can get the coal lit, and it has a nice flame and lasts all night, but we just cannot get the temperature over 230F, and so are worried about creosote forming in the flue liner. It also makes a bit of smoke come out of the chimney and stinks up the street, so I'm sure the neighbours arn't happy either!

We ensure the grate is clean so air can get up to the coals and have the vents both open (otherwise the temperature drops even further down!) but do not know how to raise the temperature (we would like it in the region of 350F really).

Any ideas?

Hi Op, you could try anthracite, usually burns very hot & lasts quite well.
We don’t use kiln dried logs anymore, as found that they did burn quickly, we use seasoned logs that we get from a local farm £90.00 worth usually last 2-4mths depending on how cold it has been.

You need to talk me through the steps here...I’ve got 3 stoves of varying output. So let’s see if we can help. I also only have 8% phone battery, but I’ll be back in the morning!!

My 6kw (so fairly comparable)....

I would use 2 squares of fire lighter and about 8 small sticks of kindling. Before lighting I’d put on about 12 lumps of smokeless coal and a very smal dried log on top of the above. Open all vents. Light. Watch. Let it run and after about 20 mins add another log.

Adding 2 logs thereafter about every 40 mins gives our large open plan living room with no radiators an ambient heat of about 23-25c.

Clean the ash every 3rd day but knock it down before lighting.

I am hinking about gettting in some anthracite, and mixing it with the other coal to bring up the temperature a bit.
How much wood do you get for £90?

So are you just using coal now?

To get a hot fire going I use a combination of about 70% wood and 30% coal.

I use 3 firefighters, plenty of kindling and balance a few bits of coal on top of the kindling nest before lighting and then add the logs.

After that it's mainly topped up with logs with a few lumps of coal chucked in every now and then to keep a good ember base.

I find that closing the vents once you have it roaring away makes it get even hotter. Close them too soon and the heat will drop.

The ash gets cleared out about once every 4 - 5 days.

Hi Alabasterangel6,

Our process is about the same as yours, but minus the logs. I've heard its bad to burn coal and logs together as they release sulphuric acid which will damage the liner, so we just use firelighters and kindling to get it going.

I've just googled the sulphuric acid thing as I hadn't heard of it in 18 years of having multi fuel stoves and it looks like whilst it's technically possible no one seems to have ever really had an issue with it.

The reason your stove isn't getting hot is because you aren't using wood and because you leave the vents open. Once you have a really good red hot ember base (you probably won't get this without wood) you can close the vents down.

We use seasoned wood but once it's going you really need to close the vents. The fuel lasts a lot longer that way and gets very hot. You're also meant to keep a bed of ash under for wood, though I can't remember why.

I agree with all the above. We’ve always combined fuel on all our stoves and never ever had an issue. The only ‘rule’ I stick to is using a meter to check the logs are under 20% moisture content.

If you’re going to buy anthracite then please please use with caution till you’ve seen how it behaves. That stuff burns bloody fierce and when I’ve used it on an open fire without caution I very nearly caused a chimney fire; it’s a very different beast to smokeless coal.

Use your smokeless and your logs, I’m sure you’ll see an improvement in output.

You asked about cost; we get one of those big square builders bag things delivered for £45. That’s mixed hardwood. Softwood is a bit pointless it just evaporated! That £45 lasts a good while - most of the winter.
We probably burn 4 logs a night max.

We use probably 2 large log baskets of wood a day but it's a 7kw stove and our main source of heating during winter. It's been on for two hours already this morning but only used two large logs so far. It will probably have the last log put on it at 8.30pm ish.

Our wood doesn't cost us anything as we chop and split it ourselves from fallen trees on our farm, currently working through a nice bit of beech from Desmond a few years ago but round here I think it's about £65 - 85 for a dumpy bag of kiln dried hardwood.

We have a fire going most of the year here (old, cold, house) and spend upwards of £800 a year on logs and half that on furnicite. We burn 15 logs per fire most days in the winter (sometimes have two going at once).

Once it is burning you just need to control the air flow correctly. Primary air feeds the fire bed, secondary air feeds the flames. Most of the energy from wood comes from burning gases released when it is heated so secondary air is the most important to get right. Once it is going close down the primary almost completely and then play around with the secondary. That should give you a long burning fire bed and allow you to control the flames for heat.

I have never checked the moisture level in my logs and have burned anthracite or furnicite all my adult life (grew up in a house with a Rayburn that ran on it). No drama or chimney fires.

I kept my multi fuel stove in for three months without it going out at all on furnicite a few years back. In fact my open fire from last night is still going this morning and that was logs only.

I buy decent logs.

Hi OP, I was thinking exactly the same as you last night watching the temperature gauge. But I went outside and looked and there’s no smoke from the smokeless fuel

The way I light it is lots of paper and kindling, throw a few lumps of coal on with a log to get it going, all vents open. Then when that’s glowing load up with coal and maybe one more small log but don’t smother the fire. Once it’s doing well then more smokeless.

I don’t think mixing in newer fires is a great idea but you can to get it going. So the fire is still hot this morning, but the therm9meter only just hovered on the ‘OK’ line. With wood it’s right in the middle.

woodheat.org/thermometers.html

I don’t think mixing in newer fires is a great idea but you can to get it going

I am not sure when (or how) this became a thing. I have got two stoves here. Multifuel stoves are just that. The installation booklets don't mention anything about not burning wood and coal together and I (and my parents) have done it forever - they are nearly 80.

My chimneys are swept at least once a year and are never an issue.

Furnicite gives me masses of heat, wood gives me a nice flame.

As long as your wood is dry enough and your stove is hot enough burning different fuels together is not a problem.

I don't have a thermometer, I just light the fire and adjust the heat so I wouldn't be able to tell you how hot they get, other than they are extremely hot.

I’m just going on what I’ve read...but on further googlin* it does seem to be mixed thoughts on this

www.stovesonline.co.uk/how-to-burn-coal.html

www.logsdirect.co.uk/blog/combining-logs-coal/
www.wilkinschimneysweep.co.uk/stove-liner-collapse-burning-the-wrong-fuel/

I have been mixing fuels for so long it wouldn't occur to me to google it.

I was brought up in a rambling old house with a solid fuel Rayburn fuelled by anthracite/furnicite and whatever else Dad got his hands on during the year.

You don't know what was being burned in the example given, crap wet wood, someone who didn't realise that they weren't burning hot enough etc., etc..

Key words in one of your links wood can contain a lot of moisture.

can.

Reading between the lines the problem is mainly caused by people using wood that has too much moisture in it.

As it happens we don't have a chimney liner which is probably why we don't give it a second thought. The chimney has been here for at least 250 years burning a combination of fuels.

Can somebody explain primary and secondary air sources please

I think that’s it, the wood has to be dry and if you have a liner maybe be more careful.

Good dry wood and smokeless fuel in an efficient woodburner with a good draft great. Or an older house where it’s all set up for burning anything. The op has black smoke coming out though which doesn’t sound good!

Maybe smokeless fuel and logs would be best for her as it’ll get it up to temperature.

Trethew. There’s usually a control at the bottom and the top. Have them both open to start. Once it’s going if you are burning wood close the bottom one and open the top as that allows air in from the top for better wood burning.

Our stove only has one control at the bottom that does both. So depends on your stove. If you know the manufacturer you can google it.

Thanks crabapple. Handbook not very helpful but I usually have a little bit of bottom open and regulate the burn with top vent. Will try with bottom closed

We burn more coal (Taybrite, which is smokeless) than logs because I don't have to attend to the fire so much. I start with plenty of crumpled newspaper, 2 firelighters, a bundle of kindling and two small very dry logs. Open both vents and light. Once the logs have caught I close the vents and let it run for 10 to 15 min, I then put the coal on top and open the vents again. The heat from the lit logs ignites the coal. Once the bed looks hot and the bottom of the lumps of coal have caught I usually close them both again, but it does depend on the weather/how well it is drawing. When we first got the stove I had terrible trouble lighting it, but discovered the logs were unseasoned and possibly damp.
The only trouble with burning coal is it makes a lot of ash, so I have to clear it every time it's used. It's a 4kw stove and keeps the room at around 21c .

Hi everyone, thank you so much for your input! I will try burning some dry logs with the coal (we do have a flue liner and it goes against everything I've been taught with fires but will proceed with caution!)

I currently have the fire going, have a good bed of red coals with some flames but temp is still only 215f even with the secondary vent closed.

Might go back to wood!

Hi Piggy, we get about one & half big builders bag for £90 plus a couple of large bags of kindling, if you are anywhere near Banstead in Surrey message me & I will give you contact details.

December 2023 using the Taybrite I bought in the summer this batch doesn't seem to be burning a efficiently as previous years. Flue has been swept and inspected. Jusy not burning very well. Anyone else have problems?