Creosote drips on loading door

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Nofossil

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This year I have the driest wood ever. It's a mix of about half poplar, with the rest being red cedar, birch, locust, cherry, and buckthorn.

My fires were very hot with occasional 'puffing' from too-rapid gasification. I ended up closing my primaries to 4mm (from 6mm last year) and closing my fan shutter to about 1/2".

The boiler is running fine, but now I'm getting liquid creosote pooling on the lower lip of the loading door opening so that once in a while some of it is dragged out when I open the door, and drips down the front. I routinely scrape away a few tablespoons of it from the loading door opening before each fire.

Has anyone else seen this? Any theories about why I'm seeing it now after all these years?

Up to this point, my EKO has been spotlessly clean other than the 'protective' layer of creosote inside the firebox.
 
I get the same thing in my Tarm usually with excessive idling. I don't have storage right now, so if the need for heat isn't very high and I have a big load in, it idles quite a bit. I know you have storage, but does your EKO idle at all?
 
Twitch said:
I get the same thing in my Tarm usually with excessive idling. I don't have storage right now, so if the need for heat isn't very high and I have a big load in, it idles quite a bit. I know you have storage, but does your EKO idle at all?

I idle for short periods if I try and push the storage tank close to the boiler outlet temp, but I'm getting the drips even when I have a burn with no idling at all. Most of my burns have no idling.
 
I too use very dry wood, almost all aspen and pine slab wood, and never yet any dripping creosote. I think the problem may be, with closing down your primary air, that you are generating more wood gas than you are pushing through the gasification chamber, that the wood gas is condensing at cooler points in the firebox, with the result being what you experience.

I definitely experience very high gasification, and resulting high stack temps, with very dry wood. Note my other thread on Gassifier Draft Control, as an attempt to bring the stack temps down. You may have subconsciously identified a potential issue in the "off-on" draft fan stack temp control, that being possible wood gas condensation in the firebox, particularly if the "off" periods are excessive.

A solution may be less-dry wood, or at least mixing in less-dry wood with the drier wood. You may want to try to naturally slow down the combustion and production of wood gas.
 
I'm positive that you know what dry wood is so there's no question there. Do you suppose you have changed the air flow enough so that you are not changing the air in the upper chamber enough? There's a cold fire going in the upper chamber. Even with dry wood we know that water is a by-product of combustion. That's why the stack on the oil boiler emits steam. Does your fire in the lower chamber look any different from before you changed the settings? I had a friend who once told me how much water I was getting out of my torpedo burner and I was astonished with the number.

I've often wondered if the 2000 degree flame cracked the H2O and burned some off the water in the lower chamber but I was concerned I would be laughed out of town if I brought it up on this forum.
 
I'm pretty sure that one of the effects of reducing primary air is to reduce primary chamber temperature. The goal after all was to reduce the rate of wood gas generation. In this case, it apparently reduced the temperature enough that I'm seeing considerable creosote condensation. There's no noticeable water or moisture associated with it, though it does harden to a nice gloss-black enamel finish when it cools.
 
That's odd!

This is the first year you are seeing the dripping and this is the first year I am not seeing the dripping. The only big difference for me is that this is the first year I am using storage with a significant reduction in idling. My wood is not bad but I bet it's not as dry as yours.
 
nofossil said:
I'm pretty sure that one of the effects of reducing primary air is to reduce primary chamber temperature. The goal after all was to reduce the rate of wood gas generation. In this case, it apparently reduced the temperature enough that I'm seeing considerable creosote condensation. There's no noticeable water or moisture associated with it, though it does harden to a nice gloss-black enamel finish when it cools.

Well that could make sense because even with a hot fire (like with last years settings) there is creosote adhering to the walls but the fire is hot enough at some point to dry it and allow it to flake. It takes a tremendous amount of heat to warm that water jacket enough to dry or partially burn that stuff. What threw me was the dripping door. I would think that the door would be hotter with no water behind it.
 
nofossil said:
....
My fires were very hot with occasional 'puffing' from too-rapid gasification. I ended up closing my primaries to 4mm (from 6mm last year) and closing my fan shutter to about 1/2".....
Now that I have all dry wood, my boiler produces extra creosote buildup on the door only with significant idling from bigger fires on the cold nights (no storage). So with no idling and dry wood, your dripping creosote doesn't make much sense. Have you tried putting the 2 settings back to where they had been to see if that stops the extra creosote from forming? One other thing that come to mind would be a worn down gasket, especially at the dripping locations, but I'm sure you've checked that out already. I've had some birch take much longer to season than most other species, but you're certainly way beyond a simple answer like that one :lol:.
 
nofossil said:
This year I have the driest wood ever. It's a mix of about half poplar, with the rest being red cedar, birch, locust, cherry, and buckthorn.

My fires were very hot with occasional 'puffing' from too-rapid gasification. I ended up closing my primaries to 4mm (from 6mm last year) and closing my fan shutter to about 1/2".

The boiler is running fine, but now I'm getting liquid creosote pooling on the lower lip of the loading door opening so that once in a while some of it is dragged out when I open the door, and drips down the front. I routinely scrape away a few tablespoons of it from the loading door opening before each fire.

Has anyone else seen this? Any theories about why I'm seeing it now after all these years?

Up to this point, my EKO has been spotlessly clean other than the 'protective' layer of creosote inside the firebox.
Sounds like the culprit is "different" firewood. I don't know the first thing about an EKO, would 5mm on the primaries work, Randy PS, you might lose that nice black gloss on the front though.
 
So it's not the door itself - it's the door flange. I think it's condensing on the sides and running down to the bottom lip. In the photo below there's a pool near the left end of the bottom lip. If the pool is deep enough, the bottom of the door 'insert' catches the top of the pool and drags it out so that it drips down the front. When hot it's the consistency of molasses. It cools quickly and is easy to scrape off of the door frame lip.

If this gets really annoying I'll try opening up the primaries. The huffing was a much more annoying problem.
 

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nofossil said:
So it's not the door itself - it's the door flange. I think it's condensing on the sides and running down to the bottom lip. In the photo below there's a pool near the left end of the bottom lip. If the pool is deep enough, the bottom of the door 'insert' catches the top of the pool and drags it out so that it drips down the front. When hot it's the consistency of molasses. It cools quickly and is easy to scrape off of the door frame lip.

If this gets really annoying I'll try opening up the primaries. The huffing was a much more annoying problem.
Nofossil, I'm assuning you have a 50hz boiler running on 60hz. Did you compensate for this? I found after 1 1/2 years that nothing takes the place of proper design draft on my Atmos. Putting a cast iron manual damper in & seeing .1wc draft on the Magnehelic really meant nothing as my boiler would take off & gassify too fast to say the least. I bent 2 of the 6 vanes on the impeller flat & I see the exact same .1 draft on the Mag. & it's like a different boiler though now I can trust it & it is very controllable. I was just wondering if you did anything about the fast spinning fan. Don't know if this might help the huffing problem, Randy
 
Could it be condensing on the supply air ducts and running down to the door lip and picked up by the door?
 
nofossil said:
So it's not the door itself - it's the door flange. I think it's condensing on the sides and running down to the bottom lip. In the photo below there's a pool near the left end of the bottom lip. If the pool is deep enough, the bottom of the door 'insert' catches the top of the pool and drags it out so that it drips down the front. When hot it's the consistency of molasses. It cools quickly and is easy to scrape off of the door frame lip.

If this gets really annoying I'll try opening up the primaries. The huffing was a much more annoying problem.


Was it huffing when you came out of idle?
 
nofossil said:
So it's not the door itself - it's the door flange. I think it's condensing on the sides and running down to the bottom lip. In the photo below there's a pool near the left end of the bottom lip. If the pool is deep enough, the bottom of the door 'insert' catches the top of the pool and drags it out so that it drips down the front. When hot it's the consistency of molasses. It cools quickly and is easy to scrape off of the door frame lip.

If this gets really annoying I'll try opening up the primaries. The huffing was a much more annoying problem.
You might want to check your HX tubes if you haven't recently done so. When I used poorly-seasoned wood in 2008, the dripping creosote in the front was accompanied by the same stuff layering on the tube walls (naturally, I was unaware at the time). It's similar to the times we get sick, and stuff comes out of both ends. Although it's probably not the case in your situation, you don't want a pile of creosote in the tubes - trust me that it's way more than an annoying problem.
 
I cleaned the HX tubes a couple weeks ago - just a bit of fly ash after half a season.

I think the condensation might be starting on the door side of the air inlets - probably the coolest surface in the primary chamber.

I run my shutter a bit more closed than factory spec, perhaps in part because of the 60hz/50hz issue. I'm pretty sure that's all you have to do to compensate.

I have too much draft at times and no barometric damper. That's on my list. Been looking for a source for a custom stainless 7" stovepipe. No joy so far.
 
nofossil said:
I cleaned the HX tubes a couple weeks ago - just a bit of fly ash after half a season.

I think the condensation might be starting on the door side of the air inlets - probably the coolest surface in the primary chamber.

I run my shutter a bit more closed than factory spec, perhaps in part because of the 60hz/50hz issue. I'm pretty sure that's all you have to do to compensate.

I have too much draft at times and no barometric damper. That's on my list. Been looking for a source for a custom stainless 7" stovepipe. No joy so far.
Nofossil, Is there some way you can"shim" the fan or impeller out some? I realize you have a pressure system. This will drop the pressure right where it would be as if you were running on 50 hz. I don't know if your shutter is on the pressure or intake side. I do know that shuttering the discharge side of my fan did not bring my boiler under control. Only the impeller modification did that & shimming the impeller away further would have also worked. Just a humble suggestion Mod., Randy
 
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