Attack Wood Gasifier DP45 Profi Operation/Draft/Troubleshooting Help

WaesNotSock

New Member
Apr 2, 2017
2
Pennsylvania
Hi All! First off, this site is sweet & has already helped me fix a bunch of little problems allowing me to run my gasifier all winter (inherited from a previous occupant of my house), so I figured why not see if the smarter, more experienced folks have to say about my troubles. I am not a very experienced wood-burner, though most of my family have traditional wood furnaces that I have some familiarity with, so my questions may be poorly worded and lacking in accurate terms. Now to the equipment...

Boiler: Attack DP45 Profi gasification boiler that was bought about 8 years ago before I lived here to heat up the ~5000 sqft open-floor (40' ceilings) log house. When it was run by the previous owners (family members), it worked very well (roaring jet sound, adequate heat in some very cold winters). It was then dormant for 2 years while the propane heat kept the house & pipes from freezing before I moved in. It is located in the unfinished basement/empty garage and was installed by a professional that delivered it. It has a flue gas ventilating impeller just below the exhaust that forces air into lower chamber & jets between top & bottom chambers to draw flue gas through coals and create the secondary burn in the lower chamber (my understanding of the gasifier process anyway, super simplified).

Flue/Chimney: Not sure exactly how tall the outside cinder block chimney is, but it was installed with the boiler, runs above the highest point of the house (say 50-60'?), and I am pretty sure has a liner. It does not have a cap (I know this would probably help with the draft issues. The boiler has an back-end horizontal 150mm (~6") flue exhasut with ~6" horiz travel straight back-> 90 deg elbow->to ~36" long vertical-> ~18" long pipe horiz into the chimney opening. There is a chimney clean-out door outside the house that I clean ~1/month. Whole chimney was swept professionally this past fall before any burning, and I took a picture of it last week which looked pretty open still. I can take a picture of the flue setup if needed, but I haven't gotten around to it yet.

Issues:
The main problem from what I can figure is that the draft is off. Last night I had a major blowback about 15 sec after opening the loading door that scared the bejesus after me, but it didn't burn me or anything else (lucky!). When I start the fire after it burns out, it always smokes, even with a window cracked/open, and always puts at least 1/4 of the smoke out of the loading door even when the fire is burning hot, forcing me to open the garage door so my upstairs doesn't fill with smoke. Also, when I close the damper and start the fan to run the gasification (what the manual says) with hot coals and all, it roars at first, but after a few minutes it stops roaring and if I open the door, its smoldering. and the flue pipe by the time I get home from work is significantly cooler than when I started in the morning. There is also a moderate amount of creosote in the burn chamber. I thought it was unseasoned wood, but even burning what I know is seasoned wood, all these problems remain. I chalk all this up to insufficient air getting into the system somehow, even with the blower running & the intake air regulator fully open (flap in back of boiler that is supposed to automatically thermo-adjust to maintain air the right intake, though I have not seen the thing actually change position). I cleaned out all of the 3 ash doors thoroughly (some creosote throughout system, but no blockages or major strictures) & regularly clean out the ash, so it's frustrating to continue to have these issues. It burned all winter& heated the house pretty well, with the propane heater only kicking on when I got home late (usually burned ~6 x 500gal tanks/winter, this year only 1.5), but I still know it is running inefficiently and the smoke/backdraft problem is worrying.

There are a few other problems, but this is already overly long and probably incoherent, so I can add more details if I forgot any. Any help would be greatly appreciated about the gasifying boiler in particular, as the manual is a direct translation from Slovakia I believe and does not offer much insight into problem-fixing, and there are no service professionals anywhere close to here.

Thanks!
 

Fred61

Minister of Fire
Nov 26, 2008
2,444
Southeastern Vt.
How dry is this wood that you know IS dry?
 

WaesNotSock

New Member
Apr 2, 2017
2
Pennsylvania
How dry is this wood that you know IS dry?
About 18 months of covered seasoning and another 6mo before that uncut. Makes hollow noise when smacked. Still wasn't enough for me, so I used one of those electric moisture things and got 14-16%. Manual for gasified says 12-20% is required. Also tried burning kiln dried wood from a mill with no improvement; still just smoldering when I came home.
 

TCaldwell

Minister of Fire
Have you cleaned the hx tubes in the boiler, or checked the draft inducer fan air flow, you mention looking up the block flue, is there a spark arrestor cap on top of the flue that could be blocked?
 

Fred61

Minister of Fire
Nov 26, 2008
2,444
Southeastern Vt.
TCaldwell has some good suggestions. Look for blockages in the HX tubes and anywhere build-up might occur.
I,m going to go back to the wood because your description of the smoke has drawn me back to it. Did you split a piece and then check the split surface with the moisture meter?