Needing help solving severe creosote problems with my Seton Wood Boiler

Hey guys, I am a newbie to this site and I am so glad I found it. I have been reading as many posts as I can, and I'm learning alot. I was hoping I can get some help solving some severe creosote problems that I am having with my Wood Boiler, which based on what I have been reading here, it is considered a Gassifier.

I have a SETON boiler that I have been running for the last 3 "UN-PLEASANT" years. I have had correspondance with the designer of the boiler, and he insists that there is nothing wrong with the design and that my only problem is draft! I have added more chimney height, up to 16ft now, however most of my creosote problem is not in the vertical section of my chimney but rather around the boiler tubes above my fire box and in the back of the boiler. This last fall I cleaned my boiler out the best it has been since it was new, and I burned "GOOD" wood part of November and December and by the end of December it was pretty much plugged up again. So basically I am only getting 6 to 7 weeks of running, before I have to tear it apart and clean it out..... I can say that once I get a good bed of coals going the boiler does not smoke too much. But I can tell when the boiler starts to plug up, because when I first start a fire it will puff smoke out the front door of the boiler for about an hour to an hour and a half. Currently I don't burn 24hours a day, so I am building a fire every night.

I can definitely go into details the design and architecture of my system, but I am not sure what is relevant. I will be happy to answer any questions anyone has, I am just trying to find out if this boiler will ever work or am I going to have to do something else.

I really really could use some help. Thank you......


Regards,

Kevin

Hi Kevin and welcome to the Boiler Room. There's quite a few people here who have the seton/ greenwood design who can help you out. I had some pretty bad creosote problems myself for my first couple of years. I think the biggest cause of my problem was that my heating load wasn't enough for the boiler, so it seldom ran wide open for any length of time to gassify.
I made all sorts of creosote scraping tools and removed the rear panel about monthly for tube scraping. I tried lots of things to address the creosote problems but finally fixed them by putting in a storage tank ( which the mfr tells you it doesn't need). I burn a "wide open" ( no cycling) 4-6 hr fire each evening to provide evening heat and recharge storage. With the boiler running wide open, I still clean the tubes, but I'm only dusting off the ash. There's zero creosote. Others here a very happy without storage, so you might want to hear their viewpoints as well.

Another thought, have you checked the draft with a draft Gage? A DweyerII costs about $35 on eBay and does the job well.

Yup, I had basically the same problem until I added storage, altho I never had a problem with smoke billowing out the feed door. That sounds like a draft problem or possibly partially plugged flue pipe. In spite of what Fred Seton states, these boilers, like most , are NOT designed to do a lot of idling. According to Fred, the longer they idle the better ! With all due respect to Fred, that is ludicrous. Fred states that any creosote that builds up during idling is quickly burnt up on the next burn cycle...also completely WRONG. Unless you can do long burns like Mole said, you are going to get creosote build up from idling.

If you can't do storage, my only suggestion is to burn the driest wood you can.

Pat

If everyone had storage, world peace would break out.

Seriously, storage is THE ANSWER for nearly any wood burning boiler. They all run cleaner with it.

Thank you for your response, I was reading some of your other posts and knew you had some real good experience with Seton Boilers.. I have been seriously considering a storage tank, since last winter. I have also changed my "firing Technique" so to speak, now I build a fire late in the evening and I force several zones on in my house including one of the zones in the concrete basement. I let the boiler run hard all night and let my house heat up pretty high and then in the morning I let the fire burn out. My boiler does fire harder than it used too, but I can say that the damper does shut sometimes.

Also with respect to checking the draft, I have not actually checked it. I know that I need to, and I can grab a Magnahelic gauge or a manometer from work.

Are you running 8" double insulated chimney pipe on yours? If so, how tall is your chimney? Currently I am coming out the back of my boiler for 2 feet with single wall stove pipe, and then I am reducing down to 6" and going through the wall into a duratech double insulated cleanout tee. From there, my chimney is 16ft tall. I also put a draft inducer in the horizontal single wall pipe coming out the back of the boiler, but I don't run it because it causes my boiler to fire too hard and over heat. I fear that, the inducer blades hanging down and not running may be slowing down my draft.

Thanks Pat for responding, I have also read many of your's and Mole's other posts and found them to be good reading. I will definitely pick your guy's brains on the storage setup and design here in the near future. I think I might have a draft problem, and I would like to get that solved first. I would like to ask you, are you running 8" chimney? If so, how high is it? You can read my response to Mole on my design, and I am just wondering If I need to go to 8". I can tell you that the wood I am burning this year is very very well seasoned, some of the best fire wood I have ever had. That coupled with firing my boiler hard all night has helped out quite a bit.

Once my boiler is heated up good, and I have a good bed of coals it seems to run pretty clean, with very little smoke. However I can tell you that I have creosote built up on the boiler tubes right above the fire box. I know it has to be running fairly hot right there, and Fred keeps telling me that I have to keep the exhaust gas above 400degF or I will build up creosote. I have hardly any creosote at the end of my chimney, but most of it is on the boiler tubes down the back of the boiler by the intake tubes and in the single wall pipe directly off the back of the boiler.

Regards,

Kevin

You should be running 8" SS chimney pipe. I have about 15' and get all the draft I need for sure. With 6" you probably need more height to get a better draft. Ideally you should go with 8", but it might be a pain to change it now?

The Setons/GW's are notorious for having the tubes, especially on the back vertical section get very clogged with creosote and junk. I actually modified my HX in mine last summer. I lowered it and moved it forward 1 1/2" The HX is now more in the exhaust path. It seems to be staying cleaner and getting better heat transfer, but probably not necessary, just something I wanted to try.

But yes, the first thing you should address is the draft. You may also want to check the draft tubes. idling causes them to collect creosote also and restrict airflow.

When I fire mine up for a burn, I get smoke for about the first 5 minutes max, then nothing but a clear heat plume for the duration of the burn. My stack temps typically run between 430F and 480F when shes ripping good

Pat

I have a home made version of the seaton and this is my 4th winter with it. ( No storage ) Build up is a common problem for me during the shoulder seasons but not when the weather stays freezing or below. When it get warmer like it is here today, I run my shop HX constant, ( Which is my dump zone ) to help keep the unit from idling less. It does cause me to burn more wood, but the trade off is worth it.

I have also learned what amount to load according to weather conditions. If its going to be sunny that day....less wood. I keep a constant fire all winter long, I hate starting new. I have also learned that with my setup, the house being a water to air HX, I have a large window or range of water temp that will work for me.

Right now I run 155 down to 110 without loosing heat in the house. With this range I can keep a perpetual fire and little build up. ( The first season I thought I had to keep it 180 always) I load morning before work.....couple pieces 10 hrs or so later when I get home.....and a load at 9 before bed. The best thing you can do is set up your unit so it's easy to clean. easily removable back panel, ( to clean the down tubes of the pressure vessel )and lower side panel ( to remove the ashes and buildup you scraped off.

The horizontal tubes can be cleaned from the load door with a little inventive tool making. I also have a simple band to remove the short straight piece and elbow from my flu to clean them out, as sum buildup occurs there. I clean mine once in the fall, ( after the temp stays down ) and then after the spring warm up. I can do this without loosing very much water temp at all. One more thing is to use a creosote remover ( as sold at Menard's in powder form ) once in a while, or just burn a few aluminum cans which seams to do the same thing. Hope this helps, just my 2cents

Jesse

Kevin,

My Seton was horribly plugged up my first two seasons and I was getting 1200F stack temperatures.

I have a W-130 without storage (soon to be corrected) with 18" horizontal 8" black stove pipe Teed to 24' of 8" DuraVent Class A stainless steel double walled pipe.

My draft is 8-11" w.c.

The beginning of this season I added a TERMOVAR 4440A-3 72C to the supply line from the w-130.

The result has been dramatic - stack temperatures between 400-500F and the hx tubes staying clean.

I did remove the side panel and clean the tubes once and I inserted a piece of angle iron across the intake tubes in front of the exhaust header.

Also, I originally only had one 3/4" pex tube from the supply to my house load and have added several lines in parallel which helped dramatically.

The main operating points I found is for this style boiler are:

1. Minimize idling - preferably by adding pressurized storage and/or more dump zones.

2. Make sure that your supply and return lines can extract at least your rated BTUs - for the W-130 this means 1-1/4" pipe or larger.

3. Provide return temperature protection - keep the return water entering the Seton at least 140F or higher.

As far as cleaning and running, check out the posts from Anthony D, for example http://www.hearth.com/econtent/index.php/forums/viewthread/11830/P0/

Steve

I have 6"single wall stovepipe into a 24ft 8"x12"masonry chimney. Draft runs. 08-.11" with 400-500F stack temp. With all the problems you have, I think its worth the small price to buy and mount a cheap draft gage rather than borrow one for a 1 time measurement. I think your improved firing technique is on the money.

I have 6" single wall stove pipe, about 3ft horizontal, then about 4' vertical into a masonry chimney

Thanks Steve, I am definitely going to be adding a water storage in the near future.. In your operating point #2, I assume when you say supply and return line's being 1-1/4" you are talking about the total area of pex tubing line's going out away from the header on the back of the boiler. Right now, I only have one 3/4" feeding my house and I have another 3/4" going to my shop, but I don't have the shop hx running yet. I am not sure exactly what my return water Temp is, I only have one gauge in the front header of the boiler. When I am running the boiler, the water temp runs at a low of 165degF up to 190degF. Most of the time it run's around 180degF.

Currently I am using my house as the dump zone's. When I build a fire in the evening I go ahead and force my high temp switch on, and that cycles 2 zones on at a time.. Unfortunately by the morning my house is very very hot... And then I let it cool off throughout the day. We don't really like running this way. I think the water storage will smooth out these temp cycles in the future.

Regards,

Kevin

Hey Jesse, thanks for the information... I am from Washington state however we did live in Lafayette IN. for 4 years back in 2001 to 2005. I was working for a CornStarch plant on the north end of town.

The first two winter's I ran my boiler, my wood was not very well seasoned and I was burning pretty much 24/7, because once I had a good bed of hot coals the boiler seem to run cleaner. However right now, I cannot get rid of that much heat.... I build a fire every night and yeah your right it kind of sucks. Although, the firebrick is usually very warm when I get home and if I chop up some kindling and stack some half rounds and 1 or 2 full rounds, and then I let that sit in that heat for an hour or so... you can literally throw a match at it and it will take off like wildfire.

Congrats on building your own, without water storage how do you keep your house from getting too hot? I suppose your shop buffers some of that. I am sure I will be in a better situation once I get my shop zones running. My shop is 32ft by 50ft with three 300ft zones in the concrete floor, that should take some heat.

Regards,


Kevin

Where do you take your stack temperatures at? And if I want to measure my draft, where should I take that measurement at? Fred says, I have to be One foot above the back of the boiler exhaust up the vertical section of pipe. In mine I would be drilling a hole into the Duratech double insulated pipe, and that stuff is expensive. I don't want to screw it up.

Regards,

Kevin

Kevin, I just drilled a 1/4" hole in the SS pipe and inserted a good BBQ thermometer. Goes up to 600F . I have the temp gauge at about eye level on the stack. I have never measured my draft, never needed to I guess.

Don't bore a hole in that double wall. It will eventually ruin it due to flue gas moisture getting in the insulation.

Thanks....I keep the thermostat in the house set at 74, with setting my aqua stat at a lower temp like mentioned above, the boiler idles less. If it gets warm out like this weekend, I turn on the shop heater.

Yeah, I wondered about that, but I made the hole so that I had to force the probe into it so it fits tight, probably very little, if any, leakage around it.

Kevin,

Based on your description and setup, I would suggest two modifications:

1. Install some sort of return water temperature control - like http://na.heating.danfoss.com/PCMPDF/ESBE TV_DS_may09.pdf. My internal heat exchanger tubes were always caked with creosote at the back and down turn until I installed the return water temperature control to keep the return water 150F or above. I have a temp/pressure gauge on both the supply and return lines.

2. Install a more 3/4" pex lines or larger supply and return lines to your house. See Table 1 in http://www.taco-hvac.com/uploads/FileLibrary/SelectingCirculators.pdf for "equivalent" number of 3/4" pex to get your rated BTUs from the Seton. Mine is a 130,000 BTU so I would need 13gpm with a 20 degree temperature drop using water. So, I would need to use three 3/4" PEX-AL-PEX supply and three 3/4" PEX-AL-PEX return lines to remove 130,000 BTU from my Seton.

Are you using a flat plate heat exchanger or is the Seton plumbed directly into your house and shop zones?
I ask to see what exchange rate you are achieving.

Steve

Welcome aboard!

As you prolly already know from either your own experienceor all the insightfulcomments above, you need to keep the refractory hot and the H2O in the tubes hot.You also need to minimize damper closed time, especially when there is a full load of fresh wood in the beast.

But a question for you ... How are you deciding how much efficiency you are losing when your tubed get caked? I can't help but wonder if you are not losing as much as you think.Heres why I wonder about that.

I installed my unit (GW100) in Jan 2007 (I'm starting my 6th year). I have no storage. I have only cleaned my back tubes twice.

Storage is probably a goal everyone should shoot for. But I'm assuming you're not going to do it this season, so we need to get you cleaner without storage for now.

Not sure of your work schedule, but shoot for 4-5 hour fires. Don't over load, and don't load too early. You want to avoid filling, then having the damper close. That = creosote production.

As far as smoke out the door goes. . . with no bypass for the smoke path, there is only so much you can do. This is the area where the design could use some enhancements. But again, that is something yer not gonna tackle this year. But . .. if you load smaller, close the door and walk away (resist that first-year urge to 'check the fire' every 20 minutes) you will minimize smoke out the load door.

Hang in there!!

Jimbo

keep in mind that fred seton built these boilers to run on pine as a primary wood source, so when you start burning other species of wood i think different things or problems come up. you really need to check your draft, also he recommends 8 inch pipe as well. also how far is the boiler from your heat load? what size circulator are you using? what is your heat load? what are you burning for wood? i ran mine for two years before i cleaned it the first time and i would say the build up was average. i then added storage, door gasket, sealed all the panels, put a gasket on the draft door, and exhaust flap that shuts when there is no call for heat. i can load it and leave it for hours on end idling with no heavy build up. now when i clean it its mostly to get the fly ash out of the back. that reminds me i didn't clean it this year.

Steve, as I mentioned above I only have one 3/4" pex tubing going into the primary side of a plate heat exchanger in the house. I am not sure of the rating on the Hex, it is the same one that came on the back of my boiler when I bought it from Fred, I just moved it into house and replaced it with a header with two supply valves and two return valves. I have not opened the lines going to shop yet. I suspect that my delta between my supply and return is not that great, but I won't know until I get some gauges in.

Are you running two aquastats, one for your damper door and one for your dumpzone? If so, what temp settings do you have them set at.... Based on all information that I am getting, it seems like you have to perfectly balance the heat load to match the boiler so you can keep the water temp just right, and yet keep the damper door open as much as possible.

Regards,

Kevin

Jim Thanks for the reply, I have not really gave any thought to losing efficiency... really because if I am understanding everything I been reading, this boiler puts out way much more than I need right now. Currently, I am forcing zones on in my house once I start a fire, just trying keep the boiler from idling. My house will get up to 77 to 80 degF after I have been running for 8 to 9 hours.

My biggest concern right now is the smoke and the frequency I have to pull the boiler apart and clean it. You should see the inside of my boiler house, you could not even tell the insulation was white. There is so much soot built up on the walls and ceiling because smoke pours out the front door when I first build a fire and when I load it. It has not always been this bad, I never seen smoke come out the front door until about half way through my second season and the boiler tubes were pretty much plugged off from creosote and ash built up. I just cleaned my chimney pipe out last weekend, and I took the back off the boiler yesterday and cleaned all the tube very well and when I built the first fire yesterday... Smoke was billowing out the front door for about an hour and half until the fire and chimney got hot.


Regards

Kevin

if you have smoke coming out around the door when its shut you dont have enough draft

I only live about 3 hours west of Fred, so I am burning pretty much the same wood he is... Mostly tammarack, lodge pole pine, and Red Fir. I am gathering that draft is probably one primary problem that I need to address. I should not have skimmped out on the 8", however I have shown Fred my chimney design and he had me add 4ft more height, I am just not sure if it is enough. My guess at this point it is not....

My house is about 65ft from my boiler room. I buried my Pex tubing about 38" under ground, and I ran the pex tubing inside a 4" perforated/corrigated drain pipe with 2" high density foam insulation on each side and above the top of the drain pipe. I am not sure if that make's sense or not, basically a laid the pipe in the ditch and built a insulation house around it. The circulator on the back of my boiler is a Taco 007 model and that goes to a plate heat exchanger in the house. The secondary side of the plate Hex is all my house zones which are on a valve manifold with a Taco 011 circulator.

The first three seasons I was building up ash in the bottom of the boiler pretty often... It would get high enough that it was almots starting to cover the combustion air intake holes in the refractory at the back of the fire box. I was probably cleaning it out every three weeks. This year my wood is very very well seasoned and not dirty, so I am not getting hardly any ash build up at all in the fire box. If I could get to the point your are, where I could leave this boiler idling without any problems, and only clean every two years I would be in heaven.

Regards,

Kevin