Stove Door Query

[system 4-50]

I noticed that when I failed to shut the main door on my stove quite as tightly as I normally do that the stove was less responsive to the air adjustment on the ashtray door. This adjustment is the only airflow control on this stove, a Puffin, and is normally far too responsive, being either roaring away, or out. My questions for all you stove experts is, would it be safe to have a 5mm gap in the rope seal on the main door, and, would I lose heat up the chimney as a result?

If it is deemed safe I will experiment with it.

[Ex Brummie]

If you have a gap in the door, then the flue draught will pull through that instead of through the fire. You won't lose heat up the chimney, as you put it, but your fire will not be as hot, and you also run the risk of CO entering the cabin.

[system 4-50]

The stove is sold as not suitable for running with the main door open. Does this imply that some stoves are? If so, how do they avoid the risk of CO poisoning? I am curious as to how this works.

[Arthur Marshall]

I think mine's a Puffin (small Villager stove).  If you have a gap in the seal on the door, you have no control at all over the airflow and (as i found when my seal went) the fire burns too hot and too fast and you neither keep it in nor damp it down properly.

If it's the same as mine, when you adjust the airflow by opening the ash pan door at an angle, yes, that's hopeless.  What i did was drill half a dozen holes in a small circle in the ash pan door to the left of the handle, one in the middle, tap the centre hole and fit a cover on it with a screw so you could open it various amounts to let more air through the holes.  Totally controllable and has worked well for years. I'll post a pic if i can find one.

Edited April 18, 2017 by Arthur Marshall
Clarity

[system 4-50]

10 hours ago, Arthur Marshall said:

I think mine's a Puffin (small Villager stove).  If you have a gap in the seal on the door, you have no control at all over the airflow and (as i found when my seal went) the fire burns too hot and too fast and you neither keep it in nor damp it down properly.

If it's the same as mine, when you adjust the airflow by opening the ash pan door at an angle, yes, that's hopeless.  What i did was drill half a dozen holes in a small circle in the ash pan door to the left of the handle, one in the middle, tap the centre hole and fit a cover on it with a screw so you could open it various amounts to let more air through the holes.  Totally controllable and has worked well for years. I'll post a pic if i can find one.

A pic would be good.

We don't seem to be having exactly the same situation. To have an established fire burning at a slowish steady pace (staying in for 12 - 18hrs) I need to have the ashpan door vent open by no more than about 2mm when viewed straight on. Slightly more and it roars away. Perhaps the ashpan door seal is not good enough and nor was its predecessor?

I was thinking that if the main door had a small opening then the draw from the flue would suck some air from this, which would bypass the actual burning coals, and reduce the draw from the ashpan door vent which goes more directly through the coals, thus giving less actual burn. But perhaps it does not work like this. And anyway, if there is a risk of CO then its a no-no. But how come old-fashioned open grate fires were allowed in houses? Didn't they have a CO risk?

[Arthur Marshall]

I'll get a pic tomorrow. Open grate fires were fine  with big and long chimneys in houses with plenty of drafts, so with loads of air movement. These days , you have to have airbricks with an open fire, and most house stoves have doors as they are much more efficient . Boats do not have efficient flues, which  makes the CO danger worse. 

[bizzard]

If the stove has a single door like a Boatman that also covers the ash pan compartment, then a small gap in the seal at the bottom of the door would draw air up through the grate and through the coals.