Question about loading / burning cycles?

[FireTime]

First off, greetings! I've been faithfully reading the sage advice of you fine folk for several weeks. I feel like I've almost earned a beginner's certification in "Wood Stove Operation" just from absorbing the collective wisdom at Hearth.com.


I noticed the following advice from the Drolet Owner's Manual; this is from section 4.4 Maintaining Wood Fires:

"Wood burns best in cycles. A cycle starts when a new load of wood is ignited by hot coals and ends when that load has been consumed down to a bed of charcoal about the same size as it was when the wood was loaded. Do not attempt to produce a steady heat output by placing a single log on the fire at regular intervals. Always place at least three, and preferably more, pieces on the fire at a time so that the heat radiated from one piece helps to ignite the pieces next to it. Each load of wood should provide several hours of heating. The size of each load can be matched to the amount of heat needed.

When you burn in cycles, you rarely need to open the stove’s loading door while the wood is flaming. This is an advantage because there is more chance that smoke will leak from the stove when the door is opened as a full fire is burning. This is especially true if the chimney connector has 90 degree elbows and if the chimney runs up the outside wall of the house." Emphasis mine.

So anyway, at least during the daytime hours and milder temperatures, I've been doing exactly -- more or less -- as Drolet advices against: loading only a single split (or maybe two splits) into the firebox at a time, as needed. How many others also load only a split or two at a time? Are we bad people for doing this? And what is the possible rationale for advising against this practice?

Do you suppose Drolet advises against this out of a simple concern about the possibility of smoke rolling out of the firebox with smaller and more frequent loads? The second quoted paragraph from Drolet sort of hints at this reasoning.

OR, is there some deeper, fundamental reason (apart from peripheral concerns about smoke escaping, etc.) for only loading a firebox of wood at a time? Am I missing something? And of course, on a cold night, I DO load a full firebox of wood. Basically, I load the stove (whether one split or a firebox full) as temperature and comfort would seem to indicate.

Btw, I don't have an issue with smoke escaping the firebox when I open the door. In fact, I'm not only happy with the draft I'm getting, but with the stove, chimney and the whole installation. Even my dog is happier with this new strange warmth in the house.

Seriously, adding a wood burning stove to my home and to my life has been one of the best decisions I've ever made.

 

[BrotherBart]

I can do one or two splits at a time and get maybe an hour per split. Or load six and get nine or ten hours of good heat. I don't try to figure it out, but it just works that way.

Mostly it probably comes from the 50% of the heat that comes from the coal stage. More coaling wood, more and higher heat.

 

[FireTime]

I can do one or two splits at a time and get maybe an hour per split. Or load six and get nine or ten hours of good heat. I don't try to figure it out, but it just works that way.

Mostly it probably comes from the 50% of the heat that comes from the coal stage. More coaling wood, more and higher heat.

Thank you, BrotherBart! I don't think I'm going to try and figure it out either.

 

[NinjaTech]

I do full loads too, top to bottom, front to back. It's just easier that way too. Load twice a day and not have to mess with it for 12 hours is nicer than adding a split every two hours. With my work schedule I couldn't do that anyway, I need it to go 10+ hours while I'm gone so the single split thing just wouldn't work, id come home to a cold house and have to relight from scratch every day.

 

[ckitch]

I think it's allot to do with not being able to get stove temp high enough to burn cleanly with one or two peices. I find it much easier to run the stove on full loads, quicker secondaries, faster heat. I sometimes throw in one or two splits just to get through to the overnight load and it doesn't burn well for me, tough to get secondaries, not much heat. I always think I should have just loaded it full.

 

[Nick Mystic]

I think when you load single splits you are going to produce more creosote in your chimney since you won't be burning as hot and you'll likely put off more smoke as a result. A better option when smaller amounts of heat are needed is to put in a smaller load using smaller splits. This will allow you to get the temperature of the stove up quicker, but since there is less fuel the fire won't burn as long, thus giving off less heat.

 

[DougA]

We do smaller loads during the day because it's more convenient. We walk by the stove constantly so it's easy to add a few chunks every few hours. I also have a wide mix of wood and use a lot of softer woods during the day. I'd love it if someone could prove that adding 3 pieces 4 times over 8 hours produces less BTU than a load of 12 identical pieces over 8 hrs. As far as creosote, as long as your burn temps are high enough, it should never be an issue. I can see adding one piece and having it smoulder but that's another matter. I also get zero smoke when opening the door carefully but I'm sure with all the bad draft threads that is not the case with everyone.

At night, I do a full load, once again, more convenient than waking up every few hours.

 

[FireTime]

We do smaller loads during the day because it's more convenient. We walk by the stove constantly so it's easy to add a few chunks every few hours. I also have a wide mix of wood and use a lot of softer woods during the day. I'd love it if someone could prove that adding 3 pieces 4 times over 8 hours produces less BTU than a load of 12 identical pieces over 8 hrs. As far as creosote, as long as your burn temps are high enough, it should never be an issue. I can see adding one piece and having it smoulder but that's another matter. I also get zero smoke when opening the door carefully but I'm sure with all the bad draft threads that is not the case with everyone.

At night, I do a full load, once again, more convenient than waking up every few hours.

DougA, I'd be interested in this experiment, too.


Thanks all for the replies and insights into your loading / burning techniques!

I should have added that I work from home about 70% of the time, so this allows me to tend (and over tend!) to the fuel load in the stove. As most of you have rightly mentioned, one big indication of the success of my more frequent fuel loading method will be that first chimney cleaning and creosote inspection. And I will update this thread once I've had a look in the chimney later in the winter.

A little bit off topic: I'm also realizing the benefit of leaving a modest ash bed in the firebox, rather than sweeping it clean at every opportunity (as I was doing). I can't fully account for this, but it seems to help maintain a longer duration of glowing coals; I suppose the ash bed helps insulate and protect the live coals from burning out as quickly. This morning I was able to re-kindle the fire without relighting from scratch; I re-kindled just from the bed of ash and coal. Pretty cool!

 

[Huntindog1]

I think the reason for the full load of wood cycles is a full box limits the amount of open space in the firebox. A full load of good dried splits leaves on a small amount of space in the top of the stove up around the secondary air coming thru tubes or a secondary manifold baffle. This small space acts like a small burn chamber for the smoke gases to ignite once the temps come up in that space and that happens more quickly and easier if the space is smaller. This same idea applies to top down fire starting as putting kindling and a fire starter on top of the main wood load gets that little space at the top heated will quickly with the quick hot fast burning fire starter and kindling. Getting temps up in the fire box is what its all about to get you into the secondary smoke gas burning mode of operation. Until the temps come up your not burning smoke and thats where a major source of the heat is. And as the heat rises and gets to operational levels you can greatly reduce the input air which helps the heat build even more . Thats why people shut down the input air in small increments of 1/4 ways to 1/3 ways so as to reduce air to reduce heat flushing up the flue and then as that allows the stove top temps to build higher you can then once again lower the input air another 1/4 to 1/3 ways. Then wait for the heat to build to an even higher level. You can load your main wood load on hot coals and still use kindling and a firestarter to help get your stove up and to that operation temps levels so as you can get the input air shut down more quickly. As if the wood is sub par people will burn up alot of their main wood load just getting the temps up into that smoke burning mode.

If your wood is really dry and your stove is really hot throwing a couple splits on should still get you some secondary flames going.
I always use secondary flames as a judge of how my burn is going except there is a time when all the gases have expired from the splits and secondary flames are done for that load cycle.

 

[Woody Stover]

I load 'er up and let 'er run. I burn in a full load once at the beginning, rather than opening the door several times and flushing heat out the flue. Gotta be a cleaner burn as opposed to throwing a couple pieces in at a time and burning them in to get the stove back up to temp. That said, maybe non-cats handle a couple pieces on the fly better, with less smoke, I don't know. Still, you are opening the door and flushing heat up the chimney. With my cat stoves, full loads give even heat output over many hours, with maybe just a couple of air adjustments along the way. Maybe a couple pieces here and there level the output of non-cats a bit, useful when outside temps are moderate.

 

[FireTime]

Huntingdog1 and Woody Stover, thanks both for the furthers insights into burning in full loads. And I've noticed that Indiana is well-represented on this forum.

Huntingdog1, I believe I follow your reasoning behind a smaller space for combustion within the firebox likely contributing to a quicker and easier burn of the smoke and gasses. And a full firebox of wood, of course, will result in this 'smaller combustion space within a combustion space'. This makes sense. And as you explain and illustrate further, I am already beginning to think in terms of quickly and efficiently getting my temps up enough to begin secondary burning. I have been making careful note of the timing/temperature and effect of closing down (or opening up) my stove's primary air control; and always in increments, as you mention.

Woody Stover, you make an interesting distinction between catalytic and non-catalytic stoves, with regard to fuel load / burning cycles. Maybe non-cat stoves do tolerate piecemeal loading better..? But then, like you point out: more frequent opening of the door just flushes heat up the chimney.


I think I'm starting to better understand the wisdom of 'burn in full-load cycles'.

Thanks, everybody!

 

[markam]

DougA, I'd be interested in this experiment, too.


Thanks all for the replies and insights into your loading / burning techniques!

I should have added that I work from home about 70% of the time, so this allows me to tend (and over tend!) to the fuel load in the stove. As most of you have rightly mentioned, one big indication of the success of my more frequent fuel loading method will be that first chimney cleaning and creosote inspection. And I will update this thread once I've had a look in the chimney later in the winter.

A little bit off topic: I'm also realizing the benefit of leaving a modest ash bed in the firebox, rather than sweeping it clean at every opportunity (as I was doing). I can't fully account for this, but it seems to help maintain a longer duration of glowing coals; I suppose the ash bed helps insulate and protect the live coals from burning out as quickly. This morning I was able to re-kindle the fire without relighting from scratch; I re-kindled just from the bed of ash and coal. Pretty cool!

I've been doing that experiment for the last 10 years. I add single logs on a regular basis to keep heat output up. I went six years without cleaning my chimney and when i finally did it, I got about a half gallon of material I couldn't ignite with a propane touch heating the material to a glowing red. I have never had smoke coming out of my insert when I open it.

Basically, do what every works best for you.