Ash Bed Theory

[BoiledOver]

Just wondering if anyone else has a tough time getting gasification on a freshly cleaned boiler.

With the Eko 25 it takes a good half of an hour to gasification after totally emptying the firebox of ash, lots of smoke pouring out the chimney top. Over the next hour or so there will be intermittent smokey periods too. To a lesser degree it happens when starting the second burn after the cleaning. From there on it is smooth sailing and only takes about a minute from lighting.

 

[warno]

I don't know much about gasifiers, other then what I've read, but I'm guessing it has to do with the boiler not being warm enough yet. From what I understand gasifers like it hot.

 

[Fred61]

Next time you clean out the firebox, add a layer of charcoal over the nozzle, add a few small dry splits in good contact with the charcoal, light it and activate bypass before the charcoal is burned away. You'll see anemic gasification but almost no smoke out the stack. Gasification takes place on the charred portion of your wood and not on the wood that has just ignited. The glowing charcoal will quickly char the fresh splits.

 

[jebatty]

Leave an ash bed in the fire box and in the bottom of the gasification chamber. If you want you can clean out the gasification tunnell. Leaving char around the nozzl is a good strategy. On a start get the flue temp up to +300F before starting gasification and make sure the temp stays up. A good quantity of kindling helps too.

 

[BoiledOver]

Leave an ash bed in the fire box and in the bottom of the gasification chamber. If you want you can clean out the gasification tunnell. Leaving char around the nozzl is a good strategy. On a start get the flue temp up to +300F before starting gasification and make sure the temp stays up. A good quantity of kindling helps too.

Normally when starting a burn, the flue temp will quickly run up to about 250 in this stove and it will be ready to close lower door, start blower and close the bypass. Actually I go by sound (which equates to the 250 stack temp) and it jumps right into the gasification. If the rumble were to cease, the stack temp drops quickly.

Am thinking about leaving a couple inches of ash in the firebox during the next cleaning and see if that will make a difference. After more thought I am wondering if the ash buildup is restricting air flow in the upper chamber. The primaries are set to whatever the manual stated. Will check the height of the air holes in the firebox to make a determination after today's burn. Was noticing that the flue temps are tough to keep down also on a freshly cleaned boiler without getting considerable huffing. When the firebox has a good ash bed, this thing cruises very well at 380F to 400F at a very slow blower speed.

 

[BoiledOver]

Next time you clean out the firebox, add a layer of charcoal over the nozzle, add a few small dry splits in good contact with the charcoal, light it and activate bypass before the charcoal is burned away. You'll see anemic gasification but almost no smoke out the stack. Gasification takes place on the charred portion of your wood and not on the wood that has just ignited. The glowing charcoal will quickly char the fresh splits.

Yeah, I agree and generally use this strategy. Do you ever clean your firebox to a bare naked state during the heating season? Just after a total cleaning is the only time this stove gives any grief.

 

[maple1]

No.

To the tough time question.

 

[Fred61]

Yeah, I agree and generally use this strategy. Do you ever clean your firebox to a bare naked state during the heating season? Just after a total cleaning is the only time this stove gives any grief.

Yes, I do clean out the firebox during the heating season but add the charcoal back over the nozzle. Follow my instructions above and you'll be shocked when that EKO instantly gasses and you won't flood the neighborhood with smoke. I batch burn and usually time my last visit to the boiler so I can shut it down when there is a good bed of charcoal left. If it burns out the charcoal I have a bucket beside the boiler that I save when I rake out the lower chamber into a screen box and separate the charcoal from the ash.
Jebatty's method works and I always did it that way in the past but the problem is that by the time you have the stack temperature up to 300 degrees, you are back to square one with the valuable charcoal burned away and back to making charcoal on the new wood or in Jim's case with kindling. No kindling needed if you fuel wood is DRY and you have placed it in good contact with the charcoal bed.
If you want to reduce "huffing" start splitting your wood larger to give you less surface area. Just be sure it has been stacked for at least 2 years. Notice that when huffing occurs there is a large bed (too large) producing more gas than the system can handle. Larger splits produce a lesser amount of char that can be ignited in the lower chamber as it is being produced rather than the excess exploding in the upper chamber.

 

[mr.fixit]

Boiled over,the slow start after cleaning probably has something to do with the time it takes to do it.
During that time all of the interior of the lower chamber cools considerably down from gasification temperatures,so when restarting it just takes time to get everything warmed up again.
Mine always smokes less after a thorough cleaning out of the ashes after it warms up again.