Help with Big Jack wood furnace

[elj4176]

We have a Big Jack wood furnace in the basement that is hooked into shared duct-work with the fuel oil furnace. We can switch between the two options. I am trying to use more wood than oil this season. We used the Big Jack a few times last year too but still pretty new to wood furnaces.

We had it kicking this weekend and I kept it above the creosote temp range by feeding it every 3-4 hours and it had us roasting. The intake was about half open to keep it in that temp range. If I shut it down further then the temp would drop. At night I loaded it up with splits and then restricted the intake almost closed to have some coals in the morning ~9 hours later. The house stayed at 70F all night and I was able to easily get it kicking again in the morning by opening the intake and adding a few splits. Got the temp raised above Creosote quickly and loaded it with splits and restricted the intake and left for work. I expect to come home to a very warm house and some coals left. Plan is to feed it when I get home and get it hot again and then restrict it until time for bed...rinse and repeat.

Is it better to let it burn hotter/faster and let it go out or restrict the air intakes to keep it going slower/longer? Seems like a bad idea to only burn it hot for a couple of hours a day and then heavily restrict the intakes for long periods (9-10 hours). I don't want to just be making ceosote all day and all night lol but that thing puts out a lot of heat if I keep it fed and up to temp.

Am I using it incorrectly or is that how I am supposed to run it? I have a magentic temp gauge on the door and one on the exit pipe in the rear that goes into the chimney and both read the same as my infrared at the same spots.

 

[Wiwarm]

I have one and I prefer to heat up the house to
73 - 74 by burning hotter in the morning. I hate smoldering the wood and basically wasting the heat. I then start a new fire when it is about 68 or 69. Works for me

 

[JRHAWK9]

I have one and I prefer to heat up the house to
73 - 74 by burning hotter in the morning. I hate smoldering the wood and basically wasting the heat. I then start a new fire when it is about 68 or 69. Works for me

The big ole city of Sobieski, eh? Parents live in Howard. Used to know an ex Van Drisse Lincoln/Mercury dealership mechanic from Sobieski years ago. He may still live there, I have no idea.

 

[Wiwarm]

Cheers from Sobieski, lol.

I have a Kuuma Vf100 in the garage waiting to get installed. My Big Jack served me well for 18 years. It developed a crack on the inside I patched with hi temp Jb Weld. Still holding for now but moving on from that hungry hippo soon. Any tips, gotchas I should think about?

House is a 2004 ranch, well insulated. 2000 sq ft. Don't have a heat Calc. I have masonry chimney up through the roof, no draft issues. I could roast us out with the Big Jack if I wanted to. We like it at about 73
Thanks in advance.

 

[brenndatomu]

I didn't have great luck with my old BJ...tried a bunch of different things, but this is what was the best (copied from a former post in the past)
OK, here is what I did to my old Yukon Big Jack.
Get some ceramic insulation blanket like they use on chimney liners, 1/2" works well. Stuff that in the air slot that runs down the sides of the firebox, right above where firebricks sit. Plug off the whole slot, except the back 4-6" or so.
Get a piece of sheet metal (1/8" to 1/4" is fine) big enough to cover the grates, all but the back 6" or so. Then you let 2-3" of ashes (at least) build up on the plate, that will be the new normal. You can still push ashes through the grate in the back, and the nice thick ash bed on the plate holds coals well, which can be shoved to the back where they can get plenty of air on reloads...that makes for easy relights. The wood will now tend to burn rear-to-front, instead of front-to-rear like before. If you think about it, this makes more sense, the wood is out-gassing (smoking) mainly in the early part of the burn, so that is when you need good secondary burn action to keep the chimney clean. Good secondary burn is accomplished much easier in the back, especially now, since this is where the fresh (and now somewhat preheated) air comes in after doing these mods.
Once the wood gets to the coals stage there is no more smoke, only clean burning.
What these two mods accomplish is to only allow air to the back of the firebox, where the fire starts well back under the baffle plates, you can get, and keep, secondary burn going much better back there. Speaking of the baffles, the factory steel ones work OK, but if you switch them out for 1" thick ceramic insulation board, cut to roughly the same size as the factory plates, it seems to keep the secondary burn going hotter/longer. I bought my board from skylinecomponents on ebay. And the 1/2" ceramic insulation blanket that I used was left over from one of my chimney re-lines.
FYI, I had installed a small glass (actually high temp ceramic) viewing port in the door so I could actually see what was going on in there. The factory secondary air system is a joke and works poorly unless you are on high fire (combustion blower running and/or air intake wide open) with a fresh load of wood. Things worked MUCH better after my mods...hotter, for longer, and cleaner. The inside of the firebox went from black, brown, and tan soot, to mainly tan and white soot.
Bottom line, flip your fire! Primary fire and secondary burn in the back, red hot coals in the front, it works out much better!
Hopefully this isn't too confusing, feel free to ask questions if it is. Happy heating!
Oh, and I quit using the Tstat/combustion blower...too much heat up the chimney, and wood burnt too fast...so at that point its basically became a whole house forced air manual wood stove...which is what worked out the best for me, with that unit anyways.

 

[JRHAWK9]

Cheers from Sobieski, lol.

I have a Kuuma Vf100 in the garage waiting to get installed. My Big Jack served me well for 18 years. It developed a crack on the inside I patched with hi temp Jb Weld. Still holding for now but moving on from that hungry hippo soon. Any tips, gotchas I should think about?

House is a 2004 ranch, well insulated. 2000 sq ft. Don't have a heat Calc. I have masonry chimney up through the roof, no draft issues. I could roast us out with the Big Jack if I wanted to. We like it at about 73
Thanks in advance.

The newer EPA furnaces don't have the raw BTU output as the old school ones.

I'd install it first and see how things go. Chances are, if your home is efficient, you won't need to do anything above and beyond the typical install. It will have a much more even heat, that's for sure.

 

[brenndatomu]

I have a Kuuma Vf100 in the garage waiting to get installed. My Big Jack served me well for 18 years

You are taking the short (smart) route...I started with an old Ashley wood/coal circulator, then the BJ, then a Yukon Husky wood/oil, then a Drolet Tundra add-on, then a Kuuma VF200, now a VF100. Each one an improvement over the last...

 

[Wiwarm]

You definitely have experience with burners. I just saw too much good with the Vf100 to pass it up.
Looks like I will be waiting until after this heating season to get this Kuuma installed, really looking forward to it.