Strange ...

The past 2 days my stove has been burning at 390-420 degrees but the room temperature has been colder. Until these past 2 days the stove was chugging along at 350 degrees and keeping the main room at around 72 - 74 degrees, but now the stove is at an average 50 degrees hotter, and the room temperature is 68 degrees. I have not touched anything on the stove at all. The only thing I did was shut the vent in the wall some so not as much fresh air was coming in behind the stove. I have a barometric damper and the stove mpd is closed all of the way.

The outside temperatures for the most part have been "fairly consistent" the past week. I am still using the same coal (nut) but have noticed there are a little more fines in what I am burning now as opposed to when I started. I would say this would not be anything to worry about, but we have a pellet stove at the far end of the house (1 1/2 story, built in 1918 with a lot of little rooms) and this also, when we do burn it, has been producing less heat in the area it is in, usually 73-74 degrees with the temps we have had, but now 68-70. Yesterday the outside temperature hit 43 and the room temp with coal stove would be about 74-75 and I would open the door for a period of time to "cool" it off in here. Not the past two days, I couldn't get the room temp up to 70. What could have changed? I checked to make sure all of the windows were closed (we had company stay over the other night and it was quite warm in here so I thought they may have opened a window a little and forgot to close it). I keep a journal of outside/inside temps; stove temps, draft settings, etc and looking at past data for comparables, my stove at 400 should keep this room at around 71-72 with the outside temp in the teens. Mornings here have been in mid 20's warming up to mid 30's/lower 40's.

Just find it strange that all of the sudden in two days I notice this drastic of a change.

Hi JohnnyV, I witness similar results when the weather patterns change as in barometric pressure in the atmosphere, not to be confused with a flue pipe barometer This is evident when the air is brisk and dry my hand fed stove loves it. Granted the outside temp plays a part in it as well but the High and Low pressures in regards to weather patterns has a significant effect on my stove's efficiency, rate of burn, temp, and draft. It can be 35* outside, but if it is raining and a low pressure system moves in then everything changes quickly and it can be frustrating trying to get the same results. I see this in my draft readings and the coal seems to act differently, I've come to the conclusion that it is not the coal. Us hand fed stove users are at a disadvantage compared to stokers and folks with direct draft and draft inducers,...I think? Do you have a manometer? I don't want to confuse you but coal fines and coal quality is also a wild card that can mess with you mind as well! Good luck and keep us up dated.

JV, give er more air--it's not magic ya know

With all of the weather changes we have had here since I started her up this season, I am thinking it is not the barometric pressure change. I am leaning more to it is the fines and smaller pieces of coal that could be having an effect. I am going to try a couple of things: first and the easiest is to sift the next batch of coal I go to load in and see if this has an effect; If no change, I am going to open the vent in the wall up more (might do this first since it is supposed to get 53 out today).

I don't have a manometer. I borrowed one to set it up and have been meaning to get one.

Fred: How would more air make the stove burn less hot but give off more heat? I may be over thinking this.

Thanks guys.

Good idea on the sifting the excess fines (slack) out.
When excess fines get into a fire bed air movement gets restricted and performance will suffer.

Here is my thought, the fresh air intake is your culprit. 2 things going on. The airflow into the room from the fresh air has changed and now you not getting as much mixing of the air around the stove, causing higher stove temps and lower air temps. It's not transfering the heat to the room as efficiently due to different air currents. And #2, by having less outside air coming in, you are changing your draft and where the air is getting pulled from. This also changes the dynamic in the room, pulling more hot air toward the stove and getting a lesser heat transfer.

I think your not getting the same convection heat transfer and that is causing alot of your difference.

There are so many varriables that can stack up to make changes too. This is just my theory

JV, ya got kind of a strange situation there & the old hit & miss theory is where you're at right now--more air was just an option to check out--with this strange getting cold/warmin up weather we're having, I think everybody with a handfired is having to play with our stoves more just to compensate--HENCE--"it's not magic"

freetown fred wrote:JV, give er more air--it's not magic ya know

It makes sense about the air. Never had to worry to much about it before. It gets colder, I close it more. It gets into the teens I usually close it all of the way. I opened the air vent in the wall behind the stove more and will see if that helps. I might not notice to much today as it is supposed to get to 53. I also sifted the fines out of the next load I am going to put into it. Won't try that right away until I see if the stove is operating better with the increased air. Slow and steady until I find the why or run out of options.

With the warm weather we had the mass of the house absorbed it and it takes a few days of colder weather for that mass to lose it and need additional heat.

I opened the outside air vent all of the way. This seemed to work, but it I am not convinced that this is exactly it yet. The temperatures outside were warm and I want to make sure that when the outside temps get close to where they were it still seems like I am getting the same readings. I am not going to try anything else for a few days (like sifting the fines). I will continue to report on this as it may help others.