Any true 12 hour burns?

So since you feed it more often but with less wood each filling are you overall using more/less/ or same amount of wood? In the summer when I am running just my domestic hot water I can get a 3 day burn out of mine with the stove temp set down to 140.

I am heating a total of around 3700 sq feet with an EBW200 Econoburn without storage. The house is old, but remodeled and "fairly" tight in comparison to what it was... but nothing like a new energy efficient home. The boiler has about twice the output needed to meet load requirements even on a -10* design temp day. The oversize scenario was done purposefully to account for burn times and thermal storage to be added at a later date. With an average mix of hard and soft woods, a burn time of 12 hours doesn't happen below say 10 or 15*. (that is an estimate) I have successfully gotten 12 hours of burn at -15* and a slight wind with a full load of well seasoned hickory splits... at the end of 12 hours, I still had a good sized coal bed and water at 170* or so. I don't generally have much hickory, so what I do have I save for the coldest nights.

The larger boiler with the larger firebox allows for longer burn times until I get the thermal storage hooked up, but at the cost of a small decrease in overall effeciency. That decrease can be effectively overcome by maintaining a nice bed of coals and a small fire with just a few splits at a time added to keep the unit in gasification as much as possible... this is easy to do when I am home... obviously not so easy when I am not, hence, the large firebox is making life easy for me.

I would like to give you what I think is an average of what my customers are experiencing, but wood quality and operating techniques vary so drastically that it's almost impossible. Not to mention a few of the installs that people did themselves leave a bit to be desired. That having been said, I would say 8 to 10 hours would be a close estimate of where a person SHOULD be with no storage, decent wood, a proper install, and some common sense.

A commons sense related short story: Tonight I actually went to visit a customer whom I called to see how things were going... he told me his burn times have only been about 5 or 6 hours, and that the EBW150 boiler didn't seem to be able to keep up with his 90' of basebaord. Obviously something was wrong so I told him I would be right over. When I got there, the first thing I checked was his firewood... that's usually the problem. This guy has the best stash of firewood I have ever seen. Cord after cord of seasoned hickory stored indoors. Ok... now I am wondering what's going on. I open the gasification chamber to see what's up... it's almost completely full of ash... then I open the firbox... no kidding... it's over half full of ash. I proceeded to show him in the "operating tips" sheet that I gave him how the ash will insulate the coals from the refractories in the upper chamber, preventing gasification and reducing efficiency... and how the ash will insulate the torch from the refractory at the bottom of the boiler, preventing gasification and reducing thermal transfer. Not to mention that once the ash is removed from the upper chamber he can get twice as much wood in. The poor guy skipped over that "tip" from the sheet I gave him... he had NEVER raked any ash out of the top chamber since he fired the boiler in late september... he was running his gasser just like a regular old outdoor wood boiler. We spent about an hour cleaning everything out and had the boiler back to peak performance. I suspect when I call him in the morning, he will be much happier.

Cheers

Just an update on my common sense story posted above,

I called the guy back sunday afternoon... it was betwen 0* and 5* saturday night. At 6 hours he went to fill the boiler to find there was almost 3 partially burned splits left inside. My guess is that would have gotten him that extra 2 hours for an 8 hour burn as advertised. He seemed pleased.

A note on his installation... he did it himself. The boiler is about 150' away from the house. The line in the ground is 1" pex... not insulated, and not O2 barrier... it's burried 3' deep inside a 4" drain pipe that is FULL OF WATER at the boiler end... who knows how far the water goes in the pipe. The ground above the line is literally soft the entire 150'. Wow, talk about heat loss. I convinced him to either move the boiler closer to the house, or replace his line. yikes.

cheers