Outdoor Wood Furnace Info
Outdoor Furnaces - Manufacturers WITH EPA-Certified Models => Portage & Main => Topic started by: Bender on December 15, 2016, 12:43:29 PM
-
Hi all,
This is my first post for me here, but I've read as much as possible trying to learn the tricks of successfully running an O 250. Mine is a bit unique. I bought it secondhand from an ex-dealer who had it sitting around for a few years. Said he had used it for half a season and decided he needed something larger. It didn't seem to have a lot of signs of use and the price was right.
Searching the postings, I believe JTS717 and I bought the stoves from the same guy. This is his post (http://outdoorwoodfurnaceinfo.com/forum/index.php?topic=6847.msg55901#msg55901 (http://outdoorwoodfurnaceinfo.com/forum/index.php?topic=6847.msg55901#msg55901)) The airbox design on his is different than mine, but other than that, the two are very similar.
The main differences between mine and the newer models seems to be:
-Firebrick. Newer models have a LOT more than mine.
-Vertical tubes. Mine has only two large tubes coming up from the reaction chamber (about 3" diameter).
-Air delivery in the firebox. Mine is delivered through dime sized holes in 2 air channels that run back-to-front, about 6" off the bottom of the firebox floor.
-Nozzle. Mine is steel (or cast iron) and has 3 large openings in it, about the size of an index finger, which run side-to-side.
I'm good about cleaning it and maintaining a 2 or 3" of ash/coals, and I generally burn good dry hardwood.
I run the air box settings about 4 or 5 turns out.
I upgraded the blower in the off season, which provides more CFM than the original.
I also just installed the siliconized door gasket because the original was leaking quite a bit.
I'm stumped though because it's still not gasifying very well. With the firebox temp at 185+, I can open the main firebox door for a minute and the fire will start burning strong, close it and watch the blow torch in the reaction chamber. This will fire strong for about a minute or two and then snuff out. When I open the main firebox door, the fire has died down and has been mostly replaced with smoke. Burn times at 10 degrees outdoors will be 2 - 3 hours for it to gain a 5 degree differential. It seems to me that it must still be starved for air.
I've thought about closing off one or two of the nozzle openings to see if that helps and possibly adding more firebrick in the next off season. I was also considering drilling a 1/4" or larger hole in the airbox and using a magnet to close a portion of it to see if, when the blower is on, the fire would actually suck additional air in through it, or if the blower would just push air out of it.
I appreciate any advice!
-
Look at your air inlets in the box closely, I bet there is creosote clogging them off.
-
Look at your air inlets in the box closely, I bet there is creosote clogging them off.
Last year I did notice some creosote dripping from the air box and had to clean it out, but haven't noticed it this year yet. Before I fired it up this year I did have a look at the inlets and they seemed ok, but thanks, I'll have a look at them again.
I'm attaching a pic of my air box innards. It's laid out horizontal whereas the new ones are roughly the same shape, but vertical. The only adjustable air disc is the center one which supplies the air below the nozzle. The 2 side discs have the bolt heads welded over to the disc. I don't they they intended them to be adjustable, but I could be wrong. I haven't seen the internals of a newer model air box. Are they similar?
(http://applebutter.com/pmo250_pics/PMO250_airbox.JPG)
-
The two on the sides would be my first step, can they be removed and cleaned?
-
A trick I learned a while back to remove creosote in bent tubes or hard to reach areas is to cut a section of fish tape used for pulling wires, slide a piece of 1/2 inch copper about 6 inches long over the fish tape,
( use the copper to hold on to the tape and guide it ) then put the cut end into your cordless drill, ( use caution and work slowly ) run the tape into the area to be cleaned gently and turn on the drill, the end of the tape will bang around and loosen the creosote.
-
The two on the sides would be my first step, can they be removed and cleaned?
I couldn't get a wrench on them, but maybe a vice grip. I can't tell if they're threaded, like the center one, or not. I'll give it a try though. Thanks!
-
A trick I learned a while back to remove creosote in bent tubes or hard to reach areas is to cut a section of fish tape used for pulling wires, slide a piece of 1/2 inch copper about 6 inches long over the fish tape,
( use the copper to hold on to the tape and guide it ) then put the cut end into your cordless drill, ( use caution and work slowly ) run the tape into the area to be cleaned gently and turn on the drill, the end of the tape will bang around and loosen the creosote.
That's a cool trick! I'll definitely give that a try. Thank you.
-
I’m not sure how tight you’re bends are, but on the waste oil boiler I built i use one of those rods for pulling wire and they can also handle a drill bit that came with it being chucked in the end of them. I simply took a wire cup brush and replaced the round shaft with an old allen wrench then ground a slot in it so it would lock in the end of the rod, the heat exchanger tubes in mine come up, make a 45 go a little further then make another 45.
-
I’m not sure how tight you’re bends are, but on the waste oil boiler I built i use one of those rods for pulling wire and they can also handle a drill bit that came with it being chucked in the end of them. I simply took a wire cup brush and replaced the round shaft with an old allen wrench then ground a slot in it so it would lock in the end of the rod, the heat exchanger tubes in mine come up, make a 45 go a little further then make another 45.
I don't think the bends are too severe in these tubes, but I will put that idea into the bag o' tricks too. I appreciate the advice.
-
I’m not sure how tight you’re bends are, but on the waste oil boiler I built i use one of those rods for pulling wire and they can also handle a drill bit that came with it being chucked in the end of them. I simply took a wire cup brush and replaced the round shaft with an old allen wrench then ground a slot in it so it would lock in the end of the rod, the heat exchanger tubes in mine come up, make a 45 go a little further then make another 45.
Oh yah, I also chuck the rod in my 18volt drill.
-
The two on the sides would be my first step, can they be removed and cleaned?
I was able to loosen the two side pipe threads and clean out the pipes using a 1/4" cable with the end frayed a bit. You can see by the pics how much crusted creosote came out. I don't think there was a complete blockage anywhere, but it's definitely breathing better now. The air box was bone dry though and looked exactly as it did when I cleaned out a couple of months ago.
I have my set point at 195 and a 5 degree differential. This morning it was down to mostly a bed of coals after a 12 hour burn and water temp was at 168 degrees. I loaded it half full with dry, split cedar. The fire took off quickly with the door open. I checked it again an hour later and the temp was still at 168 with a good fire going in the main firebox, but nothing other than light smoke in the reaction chamber. Opened the firebox door to get the fire burning hotter, closed the door and got the blow torch in the reaction chamber, which lasted for about 2-3 minutes.
I think I've got sufficient air delivery now. I left the discs for the two side air pipes open 7 or 8 turns and I can see a strong air flow feeding the fire, but I'm still scratching my head as to why it won't maintain the secondary burn in the reaction chamber. Nozzle design not restrictive enough? Not enough refractory material?
(http://applebutter.com/pmo250_pics/pm250_side_pipe_cleanout.jpg)
-
Perhaps to much air?
-
Perhaps to much air?
Could be... The thing that has me confused is why it runs really well for the first few minutes after having the firebox door open. It's like spraying ether into a carburetor. The engine runs great while it's burning the ether and then goes back to sputtering after it's burnt off.
I'll try turning the outside discs in to reduce the airflow a bit and see what happens.
Is the (center) air flow to the nozzle supposed to to create a venturi effect? Since that setting is adjustable with the airbox sealed, I have played with that quite a bit, but haven't seen it make much of a difference.
Thanks!
-
Factory nozzle? Try closing the outside ones right up to 3 complete turns out. 3/16 to 1/4 inch, way too much air. Check inside the firebox also at those air ports.
-
Factory nozzle? Try closing the outside ones right up to 3 complete turns out. 3/16 to 1/4 inch, way too much air. Check inside the firebox also at those air ports.
Yep, factory nozzle, but a prototype - made of cast iron or steel. Borrowing from JTS717's picture, it looks like the image below. I have them open about an inch each now, so that could be it. It's going to be around 20 below tonight, so it'll be a day or two before I give that a try. At least once a day I make sure the air ports are open.
Just thinking... The new blower that I put in this fall supports running at variable speeds. I haven't installed a controller for it, so it's just running full-tilt now, but if I am putting too much air into the firebox, adding that controller would be an easier test than opening the air box each time. I think the controller's only $20 or so, so I might have to put that on my christmas list.
(http://applebutter.com/pmo250_pics/pm250_nozzle.jpg)
-
When did you start having problems? I think you screwed up your air balance with that new blower that moves more CFm than the original. Why didn't you replace it with the same model of blower? These gassers are a finely tuned machine. It would be like putting a fire hose for a fuel injector into your Ford Focus and then asking why it runs awful.
I think you need to open your primary air vents just enough to keep the coal bed going well enough to break down the wood load into wood gas on top of the bed. Then you need to slowly adjust your secondary air incrimentally while checking each movement with how your secondary is reacting to your adjustments. I would say go back and buy the oem fan and you should be good to go but now you don't know where the air settings were set to. You may still have to go back to the old fan though if you can't get the balance right.
-
When did you start having problems? I think you screwed up your air balance with that new blower that moves more CFm than the original. Why didn't you replace it with the same model of blower? These gassers are a finely tuned machine. It would be like putting a fire hose for a fuel injector into your Ford Focus and then asking why it runs awful.
I think you need to open your primary air vents just enough to keep the coal bed going well enough to break down the wood load into wood gas on top of the bed. Then you need to slowly adjust your secondary air incrimentally while checking each movement with how your secondary is reacting to your adjustments. I would say go back and buy the oem fan and you should be good to go but now you don't know where the air settings were set to. You may still have to go back to the old fan though if you can't get the balance right.
It behaved pretty much the same way last year with the original fan. When I spoke with Brian at Heat Smart he suggested a stronger fan. I see your point though. It really is like a carburetor and I may have just jetted it too big.
I'll close down the intake tube discs to 1/4" out and add the variable speed controller to the blower. That should give me a chance to tweak it for optimal air flow.
Thanks.
-
That makes sense then if it wouldn't gas last year with the old fan. What's your moisture content of your wood? Yes this is just like a carb. You need to get the air to fuel balance correct. You could also cover up some of the intake on the fan to reduce CFm
-
That makes sense then if it wouldn't gas last year with the old fan. What's your moisture content of your wood? Yes this is just like a carb. You need to get the air to fuel balance correct. You could also cover up some of the intake on the fan to reduce CFm
I don't have a moisture meter, but the pile of wood I've been burning from lately is good and dry elm and cedar, some split, some 6" or smaller rounders. I hadn't considered blocking off part of the fan intake... Good idea.
I appreciate the suggestions!
-
I don't know how much gasser experience you have but I have found that rounds do not work in gassers. Basically you need a coal bed with a load of wood on top of that coal bed with full contact with the coal bed. So if you have rounds split them in half and place them flat side down onto the coal bed. Then on top of that pack your wood light tightly together with varying sizes splits as tight together as you can. This will allow the gassing process to continue as each layer of wood is broken down to coals.
-
I don't know how much gasser experience you have but I have found that rounds do not work in gassers. Basically you need a coal bed with a load of wood on top of that coal bed with full contact with the coal bed. So if you have rounds split them in half and place them flat side down onto the coal bed. Then on top of that pack your wood light tightly together with varying sizes splits as tight together as you can. This will allow the gassing process to continue as each layer of wood is broken down to coals.
This is my first gasser, so not a lot of experience. The loading method you explained makes a lot of sense and I think it explains at least some of the issues I'm having. Looking at the firebox a few hours after loading, I'm seeing a 6-8" bridge over the nozzle, where the hot coals have burned away (probably from too much air). Sounds like I need hot coals directly above the nozzle in order to get it gassing well.
My plan is to install a variable speed control this afternoon and close down the intake pipe a bit. Tweaking the air settings should be easier after that.
I'm curious, what size rounders do you generally not bother with splitting?
-
I don't have any experience with that boiler but my guess would be not enough air in the firebox. Insufficient air in the firebox can cause bridging too.
Can you open up the primary air or close off the secondary air to get more into the firebox? Did you compare the cfm vs pressure between the new blower and the old one? Just being rated at more CFM no load doesn't necessarily mean that it will supply more on the boiler.
-
it sounds like you are getting what is called "bridging". Bridging can be caused by a few different things. One of them is if the wood moisture content is to much. Like I described before in order for the gasser to operate you need a good bed of coals, on top of those coals you need a load of wood in good contact with the coal bed. That wood on top of the coal bed is heated to the point it begins to off gas and smoke but not physically " catch on fire". The wood is broken down putting off wood gas and turning into coals to replace the coals that it has consumed to turn itself into coals. If the wood is to green the coal bed will use to much energy to breakdown th green wood and th coal bed won't be able to continue self generating. If your wood is greener smaller splits help, if it is drier larger splits work better. A small split for green wood for me is in the range of 3-4 inches max. Seasoned wood I have found works well up to 6-7 inch split range. First thing I would do if I were you would be to get a good bed of coals built up. Use lots of kindling and smaller splits of hardwood for a few hours to get this nice coal bed. After you've got a good coal bed you can than place your splits stacked very tightly on top of the coal bed with everything around the 4 inch size split and see how things go. I think your going to find after a little adjustment with the air and loading it like this that it is going to start gassing and continue as long as the coal bed is being replenished.
As far as rounds I split every round until I get below 3 inches. Unfortunatly it's just the nature off a gasser.
-
it sounds like you are getting what is called "bridging". Bridging can be caused by a few different things. One of them is if the wood moisture content is to much. Like I described before in order for the gasser to operate you need a good bed of coals, on top of those coals you need a load of wood in good contact with the coal bed. That wood on top of the coal bed is heated to the point it begins to off gas and smoke but not physically " catch on fire". The wood is broken down putting off wood gas and turning into coals to replace the coals that it has consumed to turn itself into coals. If the wood is to green the coal bed will use to much energy to breakdown th green wood and th coal bed won't be able to continue self generating. If your wood is greener smaller splits help, if it is drier larger splits work better. A small split for green wood for me is in the range of 3-4 inches max. Seasoned wood I have found works well up to 6-7 inch split range. First thing I would do if I were you would be to get a good bed of coals built up. Use lots of kindling and smaller splits of hardwood for a few hours to get this nice coal bed. After you've got a good coal bed you can than place your splits stacked very tightly on top of the coal bed with everything around the 4 inch size split and see how things go. I think your going to find after a little adjustment with the air and loading it like this that it is going to start gassing and continue as long as the coal bed is being replenished.
As far as rounds I split every round until I get below 3 inches. Unfortunatly it's just the nature off a gasser.
It sounds like your G200 is a lot pickier than mine on how it is loaded. I haven't burned a lot of rounds but never had a problem with 10-12" diameter when I have put them in and have never had any bridging except when the wood was too long. Do you have the air vent clear in the back of the boiler under the drain valve?
-
I don't have any experience with that boiler but my guess would be not enough air in the firebox. Insufficient air in the firebox can cause bridging too.
Can you open up the primary air or close off the secondary air to get more into the firebox? Did you compare the cfm vs pressure between the new blower and the old one? Just being rated at more CFM no load doesn't necessarily mean that it will supply more on the boiler.
I think the problem last year was insufficient air in the firebox. Unfortunately I couldn't find any specs on the old model blower/fan. At this point all I have to go on is a visual in the firebox and it seems to be blowing strong, much stronger than with the old fan. In fact, I have to close the firebox door within 30 seconds or so if I have the fan on or I'll have a fireball shooting out 2 or 3 ft.
Just to make sure I understand, when you say primary air, you're talking about the air delivered directly into the firebox, correct? And secondary is the delivery just below the nozzle?
Thanks!
-
it sounds like you are getting what is called "bridging". Bridging can be caused by a few different things. One of them is if the wood moisture content is to much. Like I described before in order for the gasser to operate you need a good bed of coals, on top of those coals you need a load of wood in good contact with the coal bed. That wood on top of the coal bed is heated to the point it begins to off gas and smoke but not physically " catch on fire". The wood is broken down putting off wood gas and turning into coals to replace the coals that it has consumed to turn itself into coals. If the wood is to green the coal bed will use to much energy to breakdown th green wood and th coal bed won't be able to continue self generating. If your wood is greener smaller splits help, if it is drier larger splits work better. A small split for green wood for me is in the range of 3-4 inches max. Seasoned wood I have found works well up to 6-7 inch split range. First thing I would do if I were you would be to get a good bed of coals built up. Use lots of kindling and smaller splits of hardwood for a few hours to get this nice coal bed. After you've got a good coal bed you can than place your splits stacked very tightly on top of the coal bed with everything around the 4 inch size split and see how things go. I think your going to find after a little adjustment with the air and loading it like this that it is going to start gassing and continue as long as the coal bed is being replenished.
As far as rounds I split every round until I get below 3 inches. Unfortunatly it's just the nature off a gasser.
Thanks very much for taking the time to explain that. I've had a few occasions when it has worked really well, and it was exactly as you described - a good bed of hot coals in the bottom layer and the wood above looked like giant chunks of charcoal.
-
it sounds like you are getting what is called "bridging". Bridging can be caused by a few different things. One of them is if the wood moisture content is to much. Like I described before in order for the gasser to operate you need a good bed of coals, on top of those coals you need a load of wood in good contact with the coal bed. That wood on top of the coal bed is heated to the point it begins to off gas and smoke but not physically " catch on fire". The wood is broken down putting off wood gas and turning into coals to replace the coals that it has consumed to turn itself into coals. If the wood is to green the coal bed will use to much energy to breakdown th green wood and th coal bed won't be able to continue self generating. If your wood is greener smaller splits help, if it is drier larger splits work better. A small split for green wood for me is in the range of 3-4 inches max. Seasoned wood I have found works well up to 6-7 inch split range. First thing I would do if I were you would be to get a good bed of coals built up. Use lots of kindling and smaller splits of hardwood for a few hours to get this nice coal bed. After you've got a good coal bed you can than place your splits stacked very tightly on top of the coal bed with everything around the 4 inch size split and see how things go. I think your going to find after a little adjustment with the air and loading it like this that it is going to start gassing and continue as long as the coal bed is being replenished.
As far as rounds I split every round until I get below 3 inches. Unfortunatly it's just the nature off a gasser.
I’ve been burning up to 12” rounds of ash in my G400, but it is a larger firebox so probably more forgiving. I agree splits do seem to work better, but at the moment I’m still dropping and topping dead or dying ash trees, I get around 60 to 70 logs out of the woods and lined up then I’ll run the processor and have a ton of splits to use.
-
My info about running a gasser was meant to be generic. My g200 is very forgiving but I know that most gassers are not forgiving and you really need to make sure your splits are the correct sizes and the wood is stacked nice and tight and a good coal bed is established. All that being said the g200 does seem to run the best when these rules are followed but can still run 'ok' if you don't.
-
I don't have any experience with that boiler but my guess would be not enough air in the firebox. Insufficient air in the firebox can cause bridging too.
Can you open up the primary air or close off the secondary air to get more into the firebox? Did you compare the cfm vs pressure between the new blower and the old one? Just being rated at more CFM no load doesn't necessarily mean that it will supply more on the boiler.
I think the problem last year was insufficient air in the firebox. Unfortunately I couldn't find any specs on the old model blower/fan. At this point all I have to go on is a visual in the firebox and it seems to be blowing strong, much stronger than with the old fan. In fact, I have to close the firebox door within 30 seconds or so if I have the fan on or I'll have a fireball shooting out 2 or 3 ft.
Just to make sure I understand, when you say primary air, you're talking about the air delivered directly into the firebox, correct? And secondary is the delivery just below the nozzle?
Thanks!
Yes, Primary is the firebox and secondary is below the nozzles. I may have read your earlier replies wrong. I though you said that when you opened the door it would start burning good down through the nozzles and then would die off a little while after closing the door.
-
My info about running a gasser was meant to be generic. My g200 is very forgiving but I know that most gassers are not forgiving and you really need to make sure your splits are the correct sizes and the wood is stacked nice and tight and a good coal bed is established. All that being said the g200 does seem to run the best when these rules are followed but can still run 'ok' if you don't.
Ah, ok. I wasn't sure if you were talking about your or not since what you were describing is similar to what happens on the G series when the air inlet is plugged.
-
Thanks RSI, this is the only gasser that I have ever burned but I know I am spoiled when it comes to ease of use.
-
Yes, Primary is the firebox and secondary is below the nozzles. I may have read your earlier replies wrong. I though you said that when you opened the door it would start burning good down through the nozzles and then would die off a little while after closing the door.
Yes, that's exactly what happens. I open the main firebox door and get a roiling fire going, close the door and the secondary burn in the reaction chamber is strong for a few minutes and then dies out. The main firebox fire keeps going after that, it just doesn't get up to temp nearly as fast as it would if the secondary burn was going strong.
I just finished restricting the primary air tubes and installing the variable speed control for the fan. Initial testing seems about the same as before, but a less violent burn in the reaction chamber.
Tomorrow, I'll feed it the best dry, split wood I can find and load it like hondaracer suggested and see what that brings.
Thanks.
-
What happens if you restrict the secondary air way down and open up the primary air all the way? I would think that you should be getting flames pushed down the nozzles. Are the nozzles usually covered over completely or somewhat open?
How long is your chimney? Do you know if there is a minimum the MFG requires? Maybe some draft to help pull would help.
-
You restricted the primary air down and you still get a roaring fire in the firebox? What's your coal bed like?
-
What happens if you restrict the secondary air way down and open up the primary air all the way? I would think that you should be getting flames pushed down the nozzles. Are the nozzles usually covered over completely or somewhat open?
How long is your chimney? Do you know if there is a minimum the MFG requires? Maybe some draft to help pull would help.
I've tried restricting the secondary completely and having it just slightly open and it didn't seem to make too much of a difference. The nozzles generally keep themselves open, but I am noticing bridging now that I know what I'm looking for.
Chimney length is 3ft. I think P&M calls for 4ft. A bit more draft certainly wouldn't hurt though.
-
You restricted the primary air down and you still get a roaring fire in the firebox? What's your coal bed like?
After today's changes I'll have to keep an eye on it for a few days to know the full effect. I've turned the blower down by approximately 50% now. Got home tonight and the coal bed was good, but it had bridged 6-8" above the nozzle, so no secondary burn going on. As soon as I broke down the bridge and added some more dry split wood, gasification started right away and kept going for 10+ minutes while I watched it (and hopefully beyond that). Progress!! :)
-
Progress is good! It looks like bridging may be the thing that's killing your secondary. That could either be from to much primary air( I think) or wood is to high in moisture content causing you to kill the coal bed over the nozzle without being able to replenish it because the wood can't break down quick enough.
-
Any difference today?
-
Any difference today?
Had some time to play with it this morning. Adding the variable speed control helped a lot - at least for testing. Started with a good bed of coals and loaded split dry cedar on top of the nozzle, packed tight. Added some heavier (probably higher moisture) split birch on top of that. Played with the fan and the only way I could get a flame in the reaction chamber was if I slowed the fan to about 1/5 of top speed. The flame was weak at that point, but consistent. Turning the fan up would make the flame go out, but the sound of rushing air was stronger. I let it run with the weak flame for about an hour and it lost about 3 degrees overall. Turned the fan back up to 3/4 speed and checked again in an hour and it had gained 6.
With the fan blowing hard, I am gaining temp, but slowly. Could it be that it's burning the wood gases in the main firebox and not in the reaction chamber? It also makes me wonder if the nozzle design on this prototype is somehow too free flowing. The newer models all seem to have more restricted designs. I have some 1/4" steel plate that I might cut a slit in and lay it over the existing nozzle as a test.
-
Well I would say that te answer to the burning of the wood gas in the primary firebox or not is answered by looking at the smoke coming from the chimney. If you are creating the gas but the secondary flame is to strong than you should look like your running a steam engine, blowing big clouds of smoke. If you don't have much smoke I think you are burning it in the firebox. When you open the firebox door what is going on in there? I'm talking about as soon as you open the door, after 10 seconds or so you will get a Right side up fire probably. Also I'm not sure what cedar is considered as far as hard wood or soft wood? Also I'm not sure about its ability to make coals.
-
I just looked up cedar. It is the lowest btu content if any wood and it's a softwood. I think the majority of your issues lie with this. Get some quality seasoned hardwood, maple or something and give that a try. I think that may get you on track.
-
I just looked up cedar. It is the lowest btu content if any wood and it's a softwood. I think the majority of your issues lie with this. Get some quality seasoned hardwood, maple or something and give that a try. I think that may get you on track.
Hmmm... I've burned cedar in the fireplace for years and it worked well, but a fireplace and a gasser (I'm finding out) are two different beasts. :) I have a fair amount of red and white oak that I have drying for next year. I'm almost through the cedar supply for this year and then it'll be mostly elm and some birch for the remainder of this season.
Generally when I open the firebox, I'll so a whole lot of smoke for the first 10-20 seconds. I see quite a lot of smoke coming out of the stack most of the time too. I notice when it's running well that the amount of smoke coming out of the stack is reduced and it dissipates into the air quicker.
-
Try the nozzle idea also, remove the one you have, cut a half inch wide slot about 6 " long. As mentioned, put hardwood in first, cedar on top, if it's calling for heat, the higher moisture content wood will gasify.
-
If you get that much smoke there s a restriction somewhere. Do you have turbulators? Can you take a video of reaction chamber?
-
If you get that much smoke there s a restriction somewhere. Do you have turbulators? Can you take a video of reaction chamber?
Thanks Coolidge. No turbulators in this one. I generally clean the vertical and horizontal pipes with a wire brush once a week. I've noticed that the first row of horizontal tubes get finely burned ash as you'd expect, but the upper set are getting more creosote than ash. I'll take a short video of the reaction chamber in a day or two and it may take a few days before I get to the nozzle change, but I'll give that a shot too.
-
Well from your description of what you have when you open the firebox door it sounds like you don't have a right side up fire which is good. So if you have lots of a smoke(fuel)
And you have a good hot coal bed producing that smoke than what your missing is the right mixture of fuel to air. I agree that your nozzle size may need adjustment to get the right mix
-
Can you turn that steel plate sideways and use the middle slot as a makeshift nozzle? You will have to block of the other slots and any other openings.
-
Can you turn that steel plate sideways and use the middle slot as a makeshift nozzle? You will have to block of the other slots and any other openings.
Unfortunately the plate isn't exactly square, so no, I can't reorient it. I did a redesign of the nozzle this am. Just fired it back up and crossing my fingers now. I cut out the cross bars that ran sideways and installed 5/8" steel in place with about a 5/8" slot roughly 4" long running vertically. Would have liked to have run a 1/2" x 6" slot, but the space wasn't long enough to allow, so I made it the max it allowed, 4" and opened the slot up a little to 5/8". I also lightly welded the previous cut out bar pieces on the underside of the newly welded in plate. My thinking there is that the more heat that the steel can hold, the better the chance of burning the gasses. And they were just lying there... :)
Here are the pics of the redesign.
(http://applebutter.com/pmo250_pics/pm250_nozzle-redone.jpg)
-
Fingers crossed!
-
How many holes on those outside rails? Looks like some might be plugged.
-
How many holes on those outside rails? Looks like some might be plugged.
5 holes on each side. I make sure they're open with each morning fill. Poor spot for air delivery... Of course this particular unit was a prototype and that design was scrapped in the production models. I believe they made a channel that runs up the back of the firebox and delivers the air much higher up. It may be a while before I get around to making *that* modification, but that could be at least a partial cause of the poor secondary combustion. I expect that air delivered above the fire would persuade the smoke/wood gasses to be pushed down through the nozzle better than having it delivered much lower. Just curious, where is the primary air delivered on the G200?
I did a lot of trial and error testing tonight. I was mostly burning split cedar again, which thanks to HondaRacer I now understand is way low on the list of quality woods, but I figured if I tested with crap wood, things would only improve with the good stuff. With the primary air discs set about 1/4" open I played with the secondary and fan speed. Having the fan at full to half speed didn't make too much of a difference, but I did get slightly longer active burn times in the reaction chamber running the blower full bore. Next, I opened up the air box and set the primary discs open a lot farther, about an inch each, as the fire still seemed starved for air. Burn times in the reaction chamber increased 2X. Started playing around with the secondary air supply again and found that with it closed off as much as possible, burn times were significantly longer, around 4X.
I learned that tuning it by ear seemed to work the best. I open the main firebox and get a strong fire burning with good hot coals, then close it up, go around back and open the clean-out door for the vertical tubes and 1st set of horizontals. From there you can hear the jet engine sound of the secondary burn. By adjusting the secondary air supply and changing the fan speed I was able to tune it to where I thought it sounded best and lasted the longest.
I'm hoping someone that knows the Optimizer well can help me understand a couple of strange sounds that it makes sometimes. The first is a chuffing sound, kind of like an old locomotive, but faster. The other is a low whistling sound, like blowing over the top of a beer bottle if it had a 4" opening.
Thanks!
-
I have been following the thread and have some ideas but they are going in the opposite direction of where you have been going, here is my advice.
First in the reaction chamber, the early models, before EPA approval there were two rows of brick standing vertically and running lengthwise, they were intended to create a channel that directed the gasses first forward toward the door then they passed to the outside and then back to the rear of the reaction chamber, it was much like the design of the Seqouyah Paradise E 3300 and 3400 models, it seemed like a good idea at the time but after running one of the early models ( not as early as yours ) for a short time, I had an idea that the channels were restricting air flow and impinging on the secondary burn flame, this idea actually comes from the oil and gas industry, flame impingement on any oil or gas burner always makes for a dirty burn. I removed all the brick in the reaction chamber and then replaced what I needed by cutting some and laying them flat, I think the chamber was about 14 inches wide so an 8 inch brick and then a cut 6 inch brick would run across the bottom, 2 inches high and 4 inch front to back, repeat this until you have covered the entire bottom of the reaction chamber. This opens up the chamber for far less impingement as well as making it far easier to clean behind the original passages.
Nozzle, I feel you are headed entirely in the wrong direction here, you may have noticed that most of my customers have tried and are now using a nozzle that Karl K builds, he and I discussed the design of that nozzle as the one that P&M made was constantly plugging up with ash, we opened it up to about 3/4 inch wide and the full length, I think that was about 10 inches long, then we gouged 6 channels, 3 on each side about 1/2 inch wide at a 45 degree angle to allow more air at a slower velocity through the nozzle, after replacing nozzles with my customers, the comments that I got were, wow that thing just came to life and it doesn't plug anymore, there are several of those folks on here and I'm pretty sure that they will chime in!
This of course is sort of mute for you as your design is completely different, my suggestion for you would be to get rid of the metal nozzle and lay another layer of brick in the bottom of your primary firebox, start from the center creating your own nozzle by simply leaving a space between the bricks about 3/4 inch wide and the length of a brick then work your way to the outside filling the entire base with 1 layer of 1 inch brick, Coolidge actually did this with his old unit and perhaps he may have a picture of it somewhere.
I will make a crude attempt to draw a picture of the retrofit but I'm not an artist so don't expect much.
-
This is a rough idea of what I would do, the reaction chamber would be laid out the same basic way excluding the nozzle of course, a 4 1/2 inch angle grinder can be used with an inexpensive masonry blade to cut the brick, BE CAREFUL, the blade does not stop for flesh and bone, I learned from experience, hurts like hell and fingers don't work well when they are missing bone!
-
You said that you are getting a secondary burning for 4x longer now, how long is that? Have you tried quality hardwood yet?
-
I don't know why it wouldn't post before but here is that drawing again
-
You can see them here. http://www.youtube.com/watch?v=5WJns8SpQ88&list=FLYi_x_JqO5WMspfXizOU4Vg#
-
I have been following the thread and have some ideas but they are going in the opposite direction of where you have been going, here is my advice.
First in the reaction chamber, the early models, before EPA approval there were two rows of brick standing vertically and running lengthwise, they were intended to create a channel that directed the gasses first forward toward the door then they passed to the outside and then back to the rear of the reaction chamber, it was much like the design of the Seqouyah Paradise E 3300 and 3400 models, it seemed like a good idea at the time but after running one of the early models ( not as early as yours ) for a short time, I had an idea that the channels were restricting air flow and impinging on the secondary burn flame, this idea actually comes from the oil and gas industry, flame impingement on any oil or gas burner always makes for a dirty burn. I removed all the brick in the reaction chamber and then replaced what I needed by cutting some and laying them flat, I think the chamber was about 14 inches wide so an 8 inch brick and then a cut 6 inch brick would run across the bottom, 2 inches high and 4 inch front to back, repeat this until you have covered the entire bottom of the reaction chamber. This opens up the chamber for far less impingement as well as making it far easier to clean behind the original passages.
Nozzle, I feel you are headed entirely in the wrong direction here, you may have noticed that most of my customers have tried and are now using a nozzle that Karl K builds, he and I discussed the design of that nozzle as the one that P&M made was constantly plugging up with ash, we opened it up to about 3/4 inch wide and the full length, I think that was about 10 inches long, then we gouged 6 channels, 3 on each side about 1/2 inch wide at a 45 degree angle to allow more air at a slower velocity through the nozzle, after replacing nozzles with my customers, the comments that I got were, wow that thing just came to life and it doesn't plug anymore, there are several of those folks on here and I'm pretty sure that they will chime in!
This of course is sort of mute for you as your design is completely different, my suggestion for you would be to get rid of the metal nozzle and lay another layer of brick in the bottom of your primary firebox, start from the center creating your own nozzle by simply leaving a space between the bricks about 3/4 inch wide and the length of a brick then work your way to the outside filling the entire base with 1 layer of 1 inch brick, Coolidge actually did this with his old unit and perhaps he may have a picture of it somewhere.
I will make a crude attempt to draw a picture of the retrofit but I'm not an artist so don't expect much.
Hi Jim,
Funny... I did exactly what you described before this burning season. Took a 9" angle grinder with a masonry cutting wheel and sliced off the "C" channel, leaving the firebrick flat. WAY easier to clean now! Whether or not it helped it breathe better, I can't say yet.
I messed with tuning it and thought I had it dialed in last night around midnight. Got up this morning to find it at 133 degrees. (palm, forehead - forehead, palm) Turns out it does prefer a reasonable air flow in the secondary tube. It's gaining temp this morning at about 3-4 degrees per hour. No flame in the secondary, just a chuffing sound about every second, but not a ton of smoke in the firebox either, so I think it's burning the wood gasses, but more so in the main firebox than where it should be.
I've verified all air passages are open, but to my way of thinking, it's still acting as if there's some kind of blockage. Reading your explanation of your and Karl's nozzle design make more sense than ever now. I looked on the forum for a picture of one, as I read a lot of posts saying how well they work, but couldn't seem to find one. Sounds like I did go the wrong way in making the nozzle more restrictive, when what I should've done was to open it up more. I like the fire brick nozzle replacement idea! That should be fairly easy.
Thanks very much for the advice! There might be hope for this old beast yet. :)
-
You said that you are getting a secondary burning for 4x longer now, how long is that? Have you tried quality hardwood yet?
My record last night for secondary burn was around 10 minutes, but again that wasn't with quality wood. Today I'll feed it the good stuff. I'm sure that will help.
-
I don't know why it wouldn't post before but here is that drawing again
I always wondered why there wasn't any firebrick in the bottom of the firebox of this stove. I will pick the brick up and get started on that in a day or two.
Again, muchas gracias!
-
You can see them here. http://www.youtube.com/watch?v=5WJns8SpQ88&list=FLYi_x_JqO5WMspfXizOU4Vg#
Nice... I waaaaant that! :) Do you have any pictures of the nozzle from the top side or out of the stove?
I noticed some other differences too. Looks like yours has firebrick standing vertically on the outside edges of the reaction chamber. Is that right? Also looks like there's a raised firebrick directly under the nozzle. Is that fixed or movable?
Thanks!
-
I couldn't find any pictures of the topside nozzle, the one in the middle was supposed to be standing up right behind where the flame hit to try and keep ash toward the front more.
-
Any more progress on this? Can anyone else with a 250 post the nozzle dimensions and the dimensions of the secondary nozzle size?
-
Any more progress on this? Can anyone else with a 250 post the nozzle dimensions and the dimensions of the secondary nozzle size?
Yep, did some more work to make it breathe better through the nozzle as SlimJim suggested. By itself, that helped a fair amount. I also added a couple of steel pipes along the side of the firebox to help keep wood from blocking the primary air supplies.
In looking online at the new O 250 design and other gassers, I noticed that they all had firebrick very close to the secondary burn area, within inches of it in most cases. I built a C-Channel with 2" firebrick around the sides of the area where the blowtorch fires and added a 1" firebrick directly below it. My thinking here is that the firebrick getting hot and holding the heat should help ignite the gasses. This helped immensely, coupled with the more free breathing nozzle.
The last thing I tried was this morning. I removed the discs limiting the primary air flow completely. It still seemed to me that the fire in the firebox still needed more air. I played with the secondary air supply (to the nozzle area) and found that it runs best with a very small amount of air flowing there (around 1/8" of the disc open).
With all that, the results were outstanding today! I ran a mixture of cedar and elm (definitely not the best wood) and started with just a few coals around 11:00am, stove was at 179 degrees. By 12:15 it hit the set point of 195. That is the fastest I have ever had it make temp, AND - it did this with both zones in the house calling for heat the entire time! Outside temp is about 20 degrees. I checked the reaction chamber two or three times during the burn time and the blow torch was going steadily.
HUGE thanks to you, Coolidge, SlimJim and RSI for all of the suggestions and sharing your knowledge! :thumbup:
Here are the pics of the re-revised steel nozzle. SlimJim, I didn't have time to line the bottom of the firebox as you suggested yet, but opening up the nozzle as you recommended was key. I will get around to lining the firebox with the 1" brick in the next month or so, but for now, life with the boiler is good. :)
(http://applebutter.com/pmo250_pics/pm250_nozzle-redone2.jpg)
-
Awesome! I'm sure you are really excited. How many gallons in it? I know my g200 when it has a good coal bed and a good wood load in it can run 160-180 in about 20 mins and sometimes faster heating up 200 gallons. When it is gassing so so because of either end of wood load or wood load not sitting down well on coal bed it sometimes can take 30-40 mins to make that same run.
-
Awesome! I'm sure you are really excited. How many gallons in it? I know my g200 when it has a good coal bed and a good wood load in it can run 160-180 in about 20 mins and sometimes faster heating up 200 gallons. When it is gassing so so because of either end of wood load or wood load not sitting down well on coal bed it sometimes can take 30-40 mins to make that same run.
Yeah, very excited! Seems to be much less ash and I think the creosote collecting in the upper tubes burned out today. Pretty sure mine is 240 gallons. The G 200 looks like a really nice stove.
-
I think your going to really like the pm when you dial it in the way it is suppose to be.
-
I think your going to really like the pm when you dial it in the way it is suppose to be.
Just had a 16 hour burn time! Loaded it about half full last night with a mixture of elm and cedar. That same wood would have yielded 8 or 9 hours before and a lot more ash. It's a completely different stove now.
-
Let er rip
-
:post:
-
Still gassing well I assume?
-
Still gassing well I assume?
Crazy well, yeah. Not having to babysit the wood boiler is a new concept... Last year I hooked up a 120V blue LED inline with the fan wiring and mounted it on the front of the stove, so I could look out at night to see if it was running. Before this last round of mods, it seemed like that was on 75% of the time, now it's about 10%. Might have to get a second job with all this extra time on my hands. :)
Actually, with the spare time, I've been working with a friend in building a microprocessor, wifi-based boiler monitor. It monitors supply water temp, fan on/off time, ambient outdoor temp and and return water temp. If the supply water temp goes below a certain value, it will send a text alert, and it will chart the temps, running times, wood load times, wood quality, etc. via a webpage. Should be a nice tool for evaluating how well things are running. If anyone's interested, I can post some more info on it when we get the prototype finished.
-
That would be great. I would like to hook something like that up to my bl 34-44
-
I would also be interested
-
I would also be interested
It'll probably be around a month before I have the prototype running, but I'll definitely post an update when I do.
-
In for prototype details