Gassification... An art or science?

[CNY Joe]

It's been about a month since the tarm 40 was installed. We finally worked out the initial startup bugs like air in the system, etc.. Have been using it frequently now since the colder temps have set in and I have a few questions that perhaps the more experienced users can provide some insight since I'm a newbie at this-

1. I had the bypass open, lower door open, upper door closed, to get the fire going after loading it up with small pieces of kindling and larger pieces on top of that - on a hot bed of coals. I noticed small puffs of smoke and then a steady stream coming out the back of the unit above the flue area from where the vertical air vents are, adjacent to the access cover. Once I closed the lower door, the smoke stopped. Any ideas on the cause?

2. When I have a good fire going, a hot bed of coals and flue temp just above 400, gassification seems to be working as I will sometimes peak inside after opening the lower door unit, since the eye glass window tends to darken after a few burns. Secondary air is set at halfway. Even though I get the ideal gassification flame curl in the chamber, I sometimes get smoke coming out of the chimney as if I'm not gassifying at all. Any ideas on this? The chimney is a pre-fab and is fully exposed to the outside.

3. How often do you check and / or clean the flue and chimney under heavy use during the cold/winter season?

Learning one burn at a time.....

 

[pybyr]

It's been about a month since the tarm 40 was installed. We finally worked out the initial startup bugs like air in the system, etc.. Have been using it frequently now since the colder temps have set in and I have a few questions that perhaps the more experienced users can provide some insight since I'm a newbie at this-

1. I had the bypass open, lower door open, upper door closed, to get the fire going after loading it up with small pieces of kindling and larger pieces on top of that - on a hot bed of coals. I noticed small puffs of smoke and then a steady stream coming out the back of the unit above the flue area from where the vertical air vents are, adjacent to the access cover. Once I closed the lower door, the smoke stopped. Any ideas on the cause?

2. When I have a good fire going, a hot bed of coals and flue temp just above 400, gassification seems to be working as I will sometimes peak inside after opening the lower door unit, since the eye glass window tends to darken after a few burns. Secondary air is set at halfway. Even though I get the ideal gassification flame curl in the chamber, I sometimes get smoke coming out of the chimney as if I'm not gassifying at all. Any ideas on this? The chimney is a pre-fab and is fully exposed to the outside.

3. How often do you check and / or clean the flue and chimney under heavy use during the cold/winter season?

Learning one burn at a time.....

none of the above(art or science), it's some kind of addiction and/ or religion wish I could offer more on the details, but I am still spending weekends and evenings offering homage by bolting up the big metal to get it all running to begin with...

 

[Duetech]

It's been about a month since the tarm 40 was installed. We finally worked out the initial startup bugs like air in the system, etc.. Have been using it frequently now since the colder temps have set in and I have a few questions that perhaps the more experienced users can provide some insight since I'm a newbie at this-

2. When I have a good fire going, a hot bed of coals and flue temp just above 400, gassification seems to be working as I will sometimes peak inside after opening the lower door unit, since the eye glass window tends to darken after a few burns. Secondary air is set at halfway. Even though I get the ideal gassification flame curl in the chamber, I sometimes get smoke coming out of the chimney as if I'm not gassifying at all. Any ideas on this? The chimney is a pre-fab and is fully exposed to the outside.

3. How often do you check and / or clean the flue and chimney under heavy use during the cold/winter season?

Learning one burn at a time.....

#2) In my EKO 40 I will sometimes get smoke/gasification when the primary air is set at too much flow. Like burning too rich of a mix for a car too much smoke for the added air for secondary burn is bound to produce smoke. Try tapering down the amount of air supplied to the primary burn chamber. Also it is possible to to have your wood split too small and produce too much wood gas to get a complete burn ratio.

#3) With my set up it depends on the wood I burn and how much idle time I get. Over all not more than once a month.

 

[jebatty]

1. ...small puffs of smoke and then a steady stream coming out the back of the unit above the flue area from where the vertical air vents are, adjacent to the access cover. Once I closed the lower door, the smoke stopped. Any ideas on the cause?

Take the top cover off and watch where the smoke is coming from. Maybe there is a poor contact seal between the top clean-out plate and the smoke chamber. Also try leaving the top door ajar while the fire is starting. You might get quicker starting fires.

2. ..eye glass window tends to darken after a few burns.

Easy to clean - remove and wipe with lacquer thinner. Sometime some fine emery paper is needed along with the wiping. The fiber gaskets won't last too long, but you can make new ones from heavy fiber gasket material from an auto parts store.

Secondary air is set at halfway. Even though I get the ideal gassification flame curl in the chamber, I sometimes get smoke coming out of the chimney as if I’m not gassifying at all. Any ideas on this? The chimney is a pre-fab and is fully exposed to the outside.

You might be getting bridging. Search "bridging" on the forum and you will get lots of ideas on how to minimize this from occurring.

3. How often do you check and / or clean the flue and chimney under heavy use during the cold/winter season?

If you are burning dry, well-seasoned wood, probably once a year. Just for comfort level sake, you might want to check it visually after a month of two of heavy burning. I burn mostly dry pine, did check monthly for a couple of months, saw very little chimney buildup and then cleaned it last summer.

Remember to brush the hx tubes regularly. I do this about every two weeks, helps a lot to keep flue temps down. Also, if you don't have turbulators, check out the "chain turbulator" idea. These dropped my flue temps by about 100F. I still burn 400-600F, but pine burns a bit hot.
https://www.hearth.com/talk/threads/17662/P15/#192106

 

[Nofossil]

Part of my goal is to make it a science rather than an art, but I'll agree with the addiction part ;-)

After three seasons, I still haven't had to clean the flue - all I have is a light coating of fly ash.

Just a comment - the only time my bypass damper is open is (1) the 4 - 5 minute startup period before initial gasification, and (2) when I have the top door open for refueling.

Too much small wood and / or wood with too high moisture content can cause a little smoke. Are you sure that it's smoke and not water vapor?

 

[jebatty]

Just a comment - the only time my bypass damper is open is (1) the 4 - 5 minute startup period before initial gasification, and (2) when I have the top door open for refueling.

agree

 

[CNY Joe]

Thanks everyone for the insight and ideas.

Re #1 - Will definitely take a look at the contact seal to see if there's a problem. For now, I'll keep the bottom door closed and the loading door ajar to get the fire going.

Re #2 - Bridging - sure enough had that happen a fews times. Smoke vs water vapor - defintely smoke if I recall, though I have had a piece of wood or two hiss, which leads me to believe higher mositure content than what I want. I'll be picking up a moisture meter this week to see what the story is with my wood, even though its been stacked/covered since last Oct. Good idea on the gaskets as I was recently wondering about that myself. Will also experiment with the secondary air flow as I hadn't thought about it being too rich.

Re #3 - will check/clean the hx and chimney this weekend and let you know if I find anything.

Thanks again for everyones response...

Learning one burn at a time...