using wood stove query

[ik9000]

quick query with the wood stove in our holiday cottage. two vents one top one bottom of the door. when should I close which one?

[spacein_vader]

quick query with the wood stove in our holiday cottage. two vents one top one bottom of the door. when should I close which one?

Bottom one controls the amount of fresh air coming in to be combusted, so open it full to light and then probably use that one to control the strength of the fire. The top one will release more warm air into the room I'd imagine.

[Zak33]

Please dpn't be offended, but spacein_vaer isn't right.

Before i answer, please photgraph the vents and I will tell you.

I will know as soon as I see it

[Zak33]

I'm worried people will read that post and imagine that heat comes out of a hole in the stove... it does not.

A Log stove works entirely by NOT letting anything out of the stove, except up the flu... it works be being hot.

[kalniel]

You nearly always have two air vents - bottom one is air feed, yes, top one is flu exit. Neither control the heat exit - that's radiated away from the hot iron.

When air is colder than surrounding, it descends. When you start a fire, the air in the flu will be cold, so if you open it you get a draught coming down the flu and out via the front of your stove or the bottom air vent. Ie. Bad. So start with the top vent closed.

On the other hand, the bottom vent you generally start open, to feed maximum oxygen to the fire while you're at the starter stage and before the temperature of the fuel is high.

Once, and only when, the temperature is high enough to draw air upwards do you open the top vent, while using the bottom vent to control the burn rate - you don't want roaring flames, more of a red glow.

[Zak33]

You nearly always have two air vents - bottom one is air feed, yes, top one is flu exit. Neither control the heat exit - that's radiated away from the hot iron.

When air is colder than surrounding, it descends. When you start a fire, the air in the flu will be cold, so if you open it you get a draught coming down the flu and out via the front of your stove or the bottom air vent. Ie. Bad. So start with the top vent closed.

On the other hand, the bottom vent you generally start open, to feed maximum oxygen to the fire while you're at the starter stage and before the temperature of the fuel is high.

Once, and only when, the temperature is high enough to draw air upwards do you open the top vent, while using the bottom vent to control the burn rate - you don't want roaring flames, more of a red glow.

I'll expand some of that because it's a tad too specific and we don't know which stove is is question

A) each stove has different vents and I for one have a stove with three vents not two.
B) assuming the two vents are bottom and top, then yes the lower one can be open to help it start but be clear - some bottom vents are from BELOW the fuel and some are into the bottom of the fuel. Coal is burned from below, wood is always burned with air from above the ash bed. Yes you CAN open the bottom vent in that case to help it start but you'd be better with the stove door open a little and then the air sucked in, which works for a short time until the fire is going.
B part two) many stoves start best with all vents open and not by closing the top vent - it's time to experiment, but I'd not keep top air closed.
C) the upper air is often an air wash, and yes in that case, it's good to control the burn with that.....BUT...
D) on older stoves the upper control isn't always an air in.. it's a flue damper (ie a butterfly valve in the flue) which slows the burn by slowing the chimney gas flue speed of exit.
E) many stoves have an air intake at the back and they often have an adjuster hidden back there - my current and previous stove did, and everytime it cools I adjusted it for the next burn until it work perfectly.
F) the cold air in the flu is a good and valid point - to overcome that you needs a fast start of heat to push warm air up to begin the flue drawing BUT to help it IMMENSELY, open a window in the room with the stove to equalise pressure in the room and outdoors so it's easier to start the flow
G) some stoves have side air too and you can load to fuel and air from the side.

[ik9000]

thanks chaps, back home now so can't send pics anymore. Got it working, and didn't die of fumes or set the place on fire so all good.

It was very similar to this one, with a vent above and below the door.



Also re opening windows - it wouldn't equalise pressure would it? It would induce stack-effect circulation (assuming a reasonable height of chimney) and use the pressure difference to help draw air up the chimney. But in rainy cold Scotland we did not open the windows. Unless the house is hermetically sealed the air will still go up the chimney and get drawn into the room from elsewhere right enough. Particularly in an old crofter/townhouse.

[Bonebreaker777]

You nearly always have two air vents - bottom one is air feed, yes, top one is flu exit. Neither control the heat exit - that's radiated away from the hot iron.

When air is colder than surrounding, it descends. When you start a fire, the air in the flu will be cold, so if you open it you get a draught coming down the flu and out via the front of your stove or the bottom air vent. Ie. Bad. So start with the top vent closed.

On the other hand, the bottom vent you generally start open, to feed maximum oxygen to the fire while you're at the starter stage and before the temperature of the fuel is high.

Once, and only when, the temperature is high enough to draw air upwards do you open the top vent, while using the bottom vent to control the burn rate - you don't want roaring flames, more of a red glow.

We use our burner the same way, we use it nearly every night during winter (god bless for free pallets) and it's been great.

[Zak33]

thanks chaps, back home now so can't send pics anymore. Got it working, and didn't die of fumes or set the place on fire so all good.

It was very similar to this one, with a vent above and below the door.



Also re opening windows - it wouldn't equalise pressure would it? It would induce stack-effect circulation (assuming a reasonable height of chimney) and use the pressure difference to help draw air up the chimney. But in rainy cold Scotland we did not open the windows. Unless the house is hermetically sealed the air will still go up the chimney and get drawn into the room from elsewhere right enough. Particularly in an old crofter/townhouse.

glad you enjoyed it

Yes opening a windows helps because houses are quite air tight. Sucking air up a chimney is ok if some is getting into the room. Once it's HOT it's easy...but not when it's cold

As an aside, some stoves come with an air intake at the back and a "snorkel" through the wall of the house to the outside world to get fresh air in, and not to suck it through the house.

That stove is, I think, a multi fuel stove, so it burns logs OR solid smokeless fuel.

Those front lower air vents are lower than the grate inside and thats what helps coal burn well, from below. It's now called "smokeless fuel" so people don't panic about it being coal!
The air vents at the top are the primary air and are for you to conntrol the air input to control heat and speed of burn. Thats for wood burning.

Question - was it nice enough to make you think you might like a stove in future?

[ik9000]

Question - was it nice enough to make you think you might like a stove in future?

Yes, but no. I liked it, always have. There is something nice about a controlled fire. Annoyingly the door was semi-gunked up and so we didn't really get to view it unless up-close, and the viewing is half of the enjoyment for me. Heat wise it wasn't as impressive as I'd expected, but then i was coming down with a cold so body temp was all over the show.

We have a gas fire and find it more therapeutic, easier to get going and warms the room ok. No ash to sweep out - and that sweeping made quite a mess however carefully I tried to be gentle. And no need to set aside space for storage. The nail in the coffin though is where we live we are within the LMA and there is already talk of cracking down on stoves as part of improving the air quality. So not worth the investment. I'm already saddled with a diesel car I won't be allowed to drive soon. Ergo I'll stick with what we have.

[mycarsavw]

Yes, but no. I liked it, always have. There is something nice about a controlled fire. Annoyingly the door was semi-gunked up and so we didn't really get to view it unless up-close, and the viewing is half of the enjoyment for me.

When you go back next year, pick up a free newspaper en route. Scrunch it up, dab it into the old ash and then rub on the glass door. It's magic.

[Zak33]

When you go back next year, pick up a free newspaper en route. Scrunch it up, dab it into the old ash and then rub on the glass door. It's magic.

this.. although I used a bit of rag and water with the ash.. but same rules.

[Butcher]

Those front lower air vents are lower than the grate inside and thats what helps coal burn well, from below. It's now called "smokeless fuel" so people don't panic about it being coal!
The air vents at the top are the primary air and are for you to conntrol the air input to control heat and speed of burn. Thats for wood burning.

Slight correction, smokeless coal and normal house coal are not the same thing. Smokeless is higher grade coal which burns more cleanly so gives off little smoke. House coal is cheaper but messier.

I use wood in our stove, it lights best with both vents open and the door cracked, then both open door closed to run it up. Bottom vent closed really damps the fire down, even with wood.

Also wire wool cleans the door up nicely.

[philehidiot]

Just two side notes. I've been places where you're not allowed to use paper in the fire at all. It's not a major issue but paper does help a lot.

Secondly, apparently, there are some new air pollution rules coming out soon which may significantly impact these kinds of burners. I seem to remember they're due out in the next year but I really can't remember exactly. Either way, I'd not buy one just yet until it's clear what these new rules will do.

[Zak33]

Secondly, apparently, there are some new air pollution rules coming out soon which may significantly impact these kinds of burners. I seem to remember they're due out in the next year but I really can't remember exactly. Either way, I'd not buy one just yet until it's clear what these new rules will do.

that's more hysteria bud. The news last month was about "wet wood" controls but as there was utterly no detail at all about it because the dept that issued the idea didn't even use the word "seasoned" it's nigh on impossible.

[Zak33]

Slight correction, smokeless coal and normal house coal are not the same thing. Smokeless is higher grade coal which burns more cleanly so gives off little smoke. House coal is cheaper but messier.

I use wood in our stove, it lights best with both vents open and the door cracked, then both open door closed to run it up. Bottom vent closed really damps the fire down, even with wood.
.

agreed - but that's not what the Stove Marketing Depts are using...

they're using Smokeless Fuel to keep the marketing hype working and avoiding the word coal at all.

I'm a stove user and will be for a long time to come. I only use wood. I only use seasoned wood. I don't use paper to start a stove. I'm a maximum "2 match man" but mainly it's just one

Dry kindling, feather sticks and a match.