What should I expect from a woodburner?
Discussion
I've just had a Harmony woodburner installed and it takes an hour to get going and just isn't kicking out any heat. It has been installed by a hetas approved installer and I am burning seasoned hardwood (measured at 16% moisture). I get the same results with smokeless coal.
The stove is entirely recessed into the fireplace with relatively small surrounding gaps. After a few hours of burning the stove itself is 150degC and the surrounding wall is hotter. Effectively I end up with a very hot lump of metal in the lounge - but it isn't convecting any heat around the room or radiating much heat as it doesn't have much surface area.
At 9kW I was expecting that once the stove was going like the clappers the room should become unbearably hot in this weather. I actually put an extra top on after the stove had been on for a couple of hours..
The stove is entirely recessed into the fireplace with relatively small surrounding gaps. After a few hours of burning the stove itself is 150degC and the surrounding wall is hotter. Effectively I end up with a very hot lump of metal in the lounge - but it isn't convecting any heat around the room or radiating much heat as it doesn't have much surface area.
At 9kW I was expecting that once the stove was going like the clappers the room should become unbearably hot in this weather. I actually put an extra top on after the stove had been on for a couple of hours..
It does sound ok, there is a constant roaring noise when going flat out. Slowly opening the door has little effect - the flames don't really change. The installer did check the draw using a meter and says it is ok - I'm not sure how accurately he measured though as the ash tray door was open when he did this.
One thing that seems inconsistent with the instruction manual is that when I switch the air intake from all vents open to top only air the flames really die down and the glass starts to tar up. If I leave a little air coming from the bottom as well I get an inferno.
One thing that seems inconsistent with the instruction manual is that when I switch the air intake from all vents open to top only air the flames really die down and the glass starts to tar up. If I leave a little air coming from the bottom as well I get an inferno.
I know from experience that different types of wood give out varying levels of heat and the stove can take up to an hour for the body of it to fully heat up but it sounds like you are not doing anything wrong.
If the stove is fully recessed I would expect the fireplace/wall to start radiating heat into the room.
Our stove is free standing on slate with exposed flue pipe for a meter before going through the wall into the twin wall flue again installed by a HEATS installer who said I would get another 3KW of heat off the flue pipe in addition to the 5KW off the stove. Certainly feels like it in a 5*10m room :-)
If the stove is fully recessed I would expect the fireplace/wall to start radiating heat into the room.
Our stove is free standing on slate with exposed flue pipe for a meter before going through the wall into the twin wall flue again installed by a HEATS installer who said I would get another 3KW of heat off the flue pipe in addition to the 5KW off the stove. Certainly feels like it in a 5*10m room :-)
It does seem to be crammed in.
Our woodburner kicks out a lot of it's heat from the top and sides and it sounds like you are heating the fireplace and are having to wait for the heat to radiate from that instead of the burner itself.
At 9KW, it should be melting your face. Ours is 6 (I think) and we can't go near it.
Our woodburner kicks out a lot of it's heat from the top and sides and it sounds like you are heating the fireplace and are having to wait for the heat to radiate from that instead of the burner itself.
At 9KW, it should be melting your face. Ours is 6 (I think) and we can't go near it.
Mr Cheese,
Cheddar here, we live with log burners over here (NZ) and yours sounds like a good 'un (9kw is HUGE) but the recessed thing gets me.
A standalone is so much more effective (despite what the numbers may say).
You've done everything properly - moisture test on the wood, high kw output burner etc but summat's up here.
Even a 5kw burner on full wack should melt cheese in moments.....
Cheddar here, we live with log burners over here (NZ) and yours sounds like a good 'un (9kw is HUGE) but the recessed thing gets me.
A standalone is so much more effective (despite what the numbers may say).
You've done everything properly - moisture test on the wood, high kw output burner etc but summat's up here.
Even a 5kw burner on full wack should melt cheese in moments.....
Last night I used an infra-red thermometer and the wall directly above the stove was 55degC, the surrounding wall was a couple of deg higher than the other walls in the room and in the bedroom directly upstairs there was a strip of wall where the chimney runs up that was a couple of deg higher.
The chimney is lined and the flue is almost entirely enclosed within the wall so it does look like I have turned one wall of the house into a giant radiator.
The chimney is lined and the flue is almost entirely enclosed within the wall so it does look like I have turned one wall of the house into a giant radiator.
MrCheese said:
Top is about 3cm, rear is almost flush to the wall, sides are 15cm. Each wall has been lined with heat reflective material and then plastered.
Assuming the model is the Harmony 33, the minimum space required above it is 100mm, and behind it 50mm. Was an air vent fitted in the room? It may not be getting enough air to combust properly.55 deg. isn't very hot. Something is wrong.
I think I would give it it's best chance and get some totally dry softwood and try it with that.
If it still isn't performing well then there's something wrong with it or the install and is time to get your installer back or phone the manufacturer.
As said above, have you tried it with a window open? you could be starving it of air.
I think I would give it it's best chance and get some totally dry softwood and try it with that.
If it still isn't performing well then there's something wrong with it or the install and is time to get your installer back or phone the manufacturer.
As said above, have you tried it with a window open? you could be starving it of air.
http://www.euroheat.co.uk/images/product_images/21...
Guidance in this for the space needed around it. Sounds like your installer has screwed up / ignored the tech doc.
Guidance in this for the space needed around it. Sounds like your installer has screwed up / ignored the tech doc.
We've used woodburners for over 25 years and wouldn't be without one. Current one is a Stovax with a supposed 7Kw output. I would estimate it starts producing heat within 10 mins of setting the fire and is ideal for keeping the lounge toasty warm and will provide background heat for the rest of the house in winter. Now thinking of putting in another in my home office.
Your problem has to be the air gap around the stove. Ours sits almost outside the fire hole (which is the alcove built to take a fireplace) on a tiled hearth so air can circulate right round it.
Your problem has to be the air gap around the stove. Ours sits almost outside the fire hole (which is the alcove built to take a fireplace) on a tiled hearth so air can circulate right round it.
It's almost a guarantee that the problem is the space in the chamber, the tricky thing is how is it going to be resolved? Will the fireplace allow you to raise the height of the chamber, giving it the required clearance? Alternatively you could push the stove forwards out of the chamber and have the flue pipe exiting the rear rather than the top, but the hearth will have to protrude enough to comply with the regs also.
The 55deg is the wall temp - stove temp is 150C.
It is a Harmony 33.
They installed an airbrick about 3m from the stove.
The hearth is massive, extending 70cm into the room. It looks like I need to bring the stove forward and use the rear flue. Anyone have any advice on how far to bring it out - if I brought out the first 1/3 of the stove into the room it would look good and I think there would be plenty of space for air circulation. If I bring the stove right out, it is going to look silly.
By the way, thanks to everyone for contributing to this thread. It cheers me up no end that there are lots of people on PH that are willing to help out!
It is a Harmony 33.
They installed an airbrick about 3m from the stove.
The hearth is massive, extending 70cm into the room. It looks like I need to bring the stove forward and use the rear flue. Anyone have any advice on how far to bring it out - if I brought out the first 1/3 of the stove into the room it would look good and I think there would be plenty of space for air circulation. If I bring the stove right out, it is going to look silly.
By the way, thanks to everyone for contributing to this thread. It cheers me up no end that there are lots of people on PH that are willing to help out!
It may be that you are burning it with too much air, so the heat is going up the chimney.
Once it's burning properly, reduce the air inlet at the bottom of the fire so that it is nearly shut. Then close the chimney damper until it smokes, then open it a bit.
The efficiency of wood burners is due the ability of dry wood to burn with a very slow through put of air, so less heat goes up the chimney.
Apologies if I'm stating the obvious.
Once it's burning properly, reduce the air inlet at the bottom of the fire so that it is nearly shut. Then close the chimney damper until it smokes, then open it a bit.
The efficiency of wood burners is due the ability of dry wood to burn with a very slow through put of air, so less heat goes up the chimney.
Apologies if I'm stating the obvious.
MrCheese said:
The hearth is massive, extending 70cm into the room. It looks like I need to bring the stove forward and use the rear flue. Anyone have any advice on how far to bring it out - if I brought out the first 1/3 of the stove into the room it would look good and I think there would be plenty of space for air circulation. If I bring the stove right out, it is going to look silly.
It would work so much better. Have a chat with the fitter about it, nothing else will be needed apart from the extra piece/s of flue pipe.Paul Drawmer said:
It may be that you are burning it with too much air, so the heat is going up the chimney.
Once it's burning properly, reduce the air inlet at the bottom of the fire so that it is nearly shut. Then close the chimney damper until it smokes, then open it a bit.
The efficiency of wood burners is due the ability of dry wood to burn with a very slow through put of air, so less heat goes up the chimney.
Apologies if I'm stating the obvious.
The nail on head hit..... Rearrange this popular phrase Once it's burning properly, reduce the air inlet at the bottom of the fire so that it is nearly shut. Then close the chimney damper until it smokes, then open it a bit.
The efficiency of wood burners is due the ability of dry wood to burn with a very slow through put of air, so less heat goes up the chimney.
Apologies if I'm stating the obvious.
As he stated above, he has a roaring inferno......
Edited by ROB_GTR on Monday 29th August 11:41
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