e-2300 air flow problem

doctorb · January 18, 2015, 09:51:11 PM

I'm in my 6th season with my 2300, have been quite happy with it, and I thought that I had it all figured by this point. Alas, a new issue has arisen.

The air flow in my firebox, that is the holes along the perimeter of the firebox, is very asymmetric. As I face the firebox, the holes to my right are perfect, with glowing coals during the burn cycles. The holes to my left are dark, or almost so, with minimal air flow. OK, before you start typing all the maintenance things I need to do, I've done them. Holes clear and clean as a whistle. I use a metal rod as well as a snake to keep the passages clean. Wood < 20% MC. Solenoids removed and passages cleaned. Solenoids opening proper in sequence. Fan operating normally. Reaction chamber emptied. Tubes cleaned. Here's my issue....

Over the years, cracking has occurred around the air holes, especially those on the back wall of the firebox. This past year, a crack developed from one of the holes at the center of the back wall all the way laterally to the vertical slit that was cut into my model by CB. My thoughts were that this slit was to potentially help prevent cracking by allowing some expansion and contraction of the metal. Anyway, this crack has displaced a bit, (the back wall at this crack is no longer smooth, but has a "step" in it that is visible. Picture ice flows with the edge of one on top of another.) so it now permits a significant amount of airflow through it. So the back left portion of my firebox is burning great, lots of airflow there, but the left side is barely burning at all. What happens is that the wood on the right side of the firebox gets combusted, the wood at the back gets combusted, and that on the left just sits there, hoping to fall over into the center of the firebox and get burned.

I have tried and tried to see if there is a blockage at the back left corner of the airflow channels, and, to the best of my ability, I do not think that the blockage is there. It makes sense that something is impeding the airflow at that corner, but I can not identify it or clean it well. Is it possible that the cracks in the air channels of my OWB are large enough that the air flow is taking the path of least resistance and exiting, for the most part, at the back left of the firebox? That is the conclusion at which I have arrived. Any thoughts? If I did not describe my problem well enough, I would certainly be glad to elucidate further. thanks in advance for your input.

beenthere · January 18, 2015, 10:06:03 PM

db
Sure sounds like your conclusion is worthy of a good bet.

Any way to hang something (steel curtain) on the back crack to stop or impede the airflow there, and see if it will pick up on the left side? Or even let the holes on the right side also plug up some to try to get a balanced air flow? Might just be too difficult to do what I'm thinking.

But do know over time that a lot of distortion in the steel comes about with the high temps from burning wood.

stratford 50 · January 19, 2015, 05:27:16 AM

Hi Dr. B, What would happen if you were to plug the air holes that seem to be flowing properly with old socks is what I use, this would force all air to the left side, this might tell you if there is a blockage on the lower left hand corner which happened on mine. To address the cracked steel, a tube of high temp silicone spread over the crack and let it harden might tell you if that air escaping is causing insufficient air for the left side air holes. May need to weld that crack in the spring once shut down and cooled. In the archives you will find where I cut a 3.5 inch hole in the back of my firebox to aid in cleaning, you would not believe the amount of hardened creosote that came out of the back corners, My furnace is the same vintage as yours, hope this helps

stratford 50 · January 19, 2015, 05:42:47 AM

Dr. B, another thought, in the spring cut out a piece in the back plate that is cracked making this your cleanout access point, this would solve 2 problems, crack would be gone a cleanout door/ panel could be installed to aid in cleaning those hard to get at back corners. If you notice on the pictures I posted all the back air holes are purposely blocked to force all the air down the sides and this has worked for several years.

thecfarm · January 19, 2015, 06:30:17 AM

There is furnace cement that could be used too. That MIGHT be better than a welding job.

doctorb · January 19, 2015, 08:16:06 AM

First, thanks to the thoughtful replies. I have tried piling up the coal bed and even packing it down, covering the air holes that are working well in an attempt to shunt the airflow to the left side of the stove. As a test, I'll try the old sock plugs. And certainly the furnace cement idea may help as well. I really like the idea of a "clean-out hatch" would make this portion of the maintenance much. much easier. I believe that I read somewhere that CB now has a kit similar to this idea that they can retrofit to your stove.

My bet is that the back left corner is not completely obstructed, but close to being so.

I am trying to "milk" this problem along until mid-February, when we have a vacation and will have the stove completely shut down for a week. I have always loaded my stove front to back. I am going to load it today with the logs sideways and piled toward the back of the stove to see if I get more efficient burning. Fortunately, it's not been bitter cold of late, so this diminished efficiency has not caused any heating problems. I think if we were having 5 degree nights and 20 degree high temps that the stove would run 24/7. After seeing some of the temps around the country in the first week or so of January, many of you would call a 5 degree/20 degree day balmy!

bobby s · January 25, 2015, 12:30:18 PM

Any luck figuring it out doc? Once in a while I'll run a rod through each hole in the firebox to loosen up any creosote hiding in there. Then I take the top solenoid off in the airbox and put the shop vac on the tube for a few minutes. I was amazed how much junk gets sucked out. This might clear things up a bit in there for you.
Also, three or four of my airholes have large vertical cracks and I still seem to have good airflow at the front of the firebox.

garret · January 25, 2015, 05:55:22 PM

Sorry to hear about the cracking. Doesn't sound like an easy fix.
I'm new to this game and have a newer model (E-2400, 2014) that doesn't suffer to the same degree from chronic obstructive firebox asphyxia, but do recognize the benefit of the periodic burnouts of creosote accumulations in the firebox. Please don't take this the wrong way, but that door-opened, burn out the goo trick that involves defeating the primary air interlock switch (which I have done), may induce excessive firebox temperatures. You mentioned on several occasions that you must start this procedure at the bottom of the burn cycle, as the water temperature will steadily increase perhaps to excessive levels. That metal is going to expand more that usual and localized higher than normal temperatures and cycling may have been a contributing factor to cracking over time. Just pointing out that during normal operation, the higher temperatures reside lower along the combustion path and in proximity to the refractory, not intended or designed for higher in the firebox.

doctorb · January 28, 2015, 07:55:53 PM

Garret-

An insightful post. I agree with your assessment. Whether I have contributed to this problem, I'll never really know. I won't completely give up the open door burn test, as it remains the best way to see what your stove is doing. I have seen the water temps rise if this is continued too long, but I've never had a water temp problem as I only start the test with the temp at the low end of my cycle.

I have contacted CB and spoken to some very helpful people. I have a kit coming which consists of a right and left sided panel for the back wall of the stove which should cover the gap created by the crack and return normal air flow.

I shut down the stove this past weekend and was able to get in there and really clean and check out the back left corner of the air channel as suggested by bobby s. No, absolutely no blockage. So my problem is from the altered air flow and will be corrected when this part (under warranty BTW) is installed. Instead of welding, it attachers with 4 bolts. I'll let you know how the fix progresses.

bobby s · January 28, 2015, 08:26:48 PM

Thanks for keeping us posted- I'll probably end up doing the same thing with the new panels. Post some pictures if you can, glad to hear parts are under warranty.

garret · January 29, 2015, 06:07:16 AM

Doc,
Glad to hear there is a fix that doesn't involve a more invasive procedure as welding. Also, the outcome of a welded patch can be closely correlated with the welder's skills (these can be all over the map). Apparently, CB is aware of this issue having fabricated a patch kit.

Good Luck

firechief · January 29, 2015, 03:01:19 PM

Doc,

You and I both have the same year 2300 and I also have the gap that you spoke of. Great to hear that it is covered by warranty.
Did you go directly through CB or through your dealer for the warranty. Thanks

doctorb · January 29, 2015, 09:39:11 PM

firechief-

As it turns out, my dealer for the last 6 years is no longer a dealer. I never had a problem with him, but I understand a few others may have. I don't know the details of his departure. These things are often a "You can't fire me. I quit" situation. anyway, I called CB directly. Got lots of good info and help from them, including email instructions on how to attach these back panels. So I am pleased with that part of this.

But they only deal through dealers. They would not send me the kit directly.

I used their website to find dealers "near" me. The closest is 31 miles away. I talked to this gentleman on the phone a couple of times during this event, and he seems interested, energetic, and knowledgable. He is not interested enough, however, to drive down here, deliver the kit, and install it. So I'll do that myself or have to find someone else to do it for me. I've got 2 total hips and had back surgery this summer, so I do not relish climbing into my firebox to drill holes in my steel. BTW, they include the drill bit and tap with the kit. Supposedly, all I need is a drill and some ear plugs..

My new dealer told me that I will have to sign a warranty form when I pick up the kit. I first heard that this was a warranty item on the phone with CB. My dealer checked with them when he ordered the part, and they confirmed it to him.

beenthere · January 29, 2015, 10:31:27 PM

Aha! Answers my question about how long you will be down.

Might suggest getting some drill bit extensions to reach the back wall without climbing into the chamber.

Might run a $100 bucks or so, but might be worth it if you end up having to do it yourself.

Holding the steel panels up while drilling may be the tough part, but the bits and tap and turning in the tap screws seems would be workable.

WI Fire · February 05, 2015, 09:58:38 AM

Doc,
While you are shut down, can you please post a picture of the problem, and a picture of the kit fix with part numbers? My serial number reflects it was among the earlier units in 2008. It later went back for refurbishment, but I am curious to see the problems that may be encountered, and the fixes as proposed by Central Boiler. As with my earlier posts regarding the refractory updates, I am happy to see that CB does R&D for support of older units as problems evolve. Thanks

doctorb · February 05, 2015, 10:27:15 AM

Pics are toward the end of this thread regarding freezing.....

https://forestryforum.com/board/index.php/topic,80986.0/all.html#lastPost

I am hesitant to post the serial number of the kit to fix this problem, because they may have different kits for certain serial number stoves, as the 2300 design changed over a period of time. So, to get the correct kit for you, you will need to call CB /or your dealer.

As you can see by the winter shutdown thread, there's some interesting info on water temp during shutdown as well as info regarding the fix. This kit was under warranty and I only paid shipping. I am up and running and it's working very well.

Logging logginglogging · February 07, 2015, 09:22:56 AM

I bought mine used, and I don't have a warrantee, so they wont help me find the kit, I do have the same stove as you though, please post the number of the kit so I can get one if needed.
Thanks

xalexjx · February 23, 2015, 08:58:34 PM

I never saw this post, mine too had similar issues. made some modifications two years ago and have never had a problem since, I took an 2" hole saw and drilled a hole where the primary air tube comes out (my side air channels no longer work) and i removed the damper bypass door and cut a 1.5"x4" slit and inch up from the bottom. I burn more wood as i dont get a full gassification effect it was designed to and i notice i have to split the wood as full chunks bridge and dont fall down. Since i have done this all I do is clean the ash pan every week or so and pull the elbows of the air tubes once or twice a winter, no other issues.