# Tarm 404 - Question about coal baffles for burning anthracite



## jsbruns (Feb 6, 2011)

Greetings-

I'm new to the site but have been reading various posts regarding coal burning and coal burning furnaces. We recently moved into a house equipped with a 1981 Tarm 404 wood/coal furnace along side a newer oil burning furnace. Considering the cost of home heating oil, I was anxious to figure out how to burn coal as either a supplement to my oil furnace or an alternative. I read through the operation manual and thought I had a pretty good understanding of how to burn anthracite. I bought several bags and gave it a shot. 

Unfortunately, after half a dozen attempts I was growing increasingly frustrated as I could get the fire started okay, but it would end up going out after 2-3 hours. I eventually found a post on this site that complained about similair struggles in his Tarm 500 series, which apparently is an identical model to my 400 series. Someone mentioned that in order to burn coal, a coal conversion kit was required, which consists of a 3 piece coal baffle setup. A few folks mentioned that they had purchased coal baffles from Tarm in NH for around $255. So, I called Tarm and talked to someone in the parts department who told me that the coal baffles are either $255 or $265, depending on if my furnace was a 402 or 404 model. At the time I wasn't sure which model I had, so I went home later that day and determined it was a 404. I called Tarm the next day and this time someone different picked up and told me that whoever had quoted me the price yesterday was wrong, the price is actually around $600 ($200/ea for the upright baffles and $190 for the base plate). 

I'm confused because not only was I given a price of $255 during my first call, but I've read several online posts in which Tarm owners said they paid $255 for these baffles before they started burning coal. I'm wondering if these baffles are available from anywhere other than Tarm, such as maybe a Tarm dealer. I know that it's often cheaper in other industries to buy from a dealer than direct from the manufacturer. Secondly, I'm wondering if anyone has attempted fabricating the baffles themselves. I'd be willing to give it a shot if I had some specs or a detailed picture to go off of. The only thing I've been able to find is a pdf bulletin from Tarm with instructions on installing the baffles. The pdf was originally scanned and the image quality is poor.

http://www.woodboilers.com/uploads/public/Coal Baffle Instructions.pdf

I read somewhere that the webmaster a former owner of Tarm, so hopefully this is a good place to ask this question.

Thanks in advance for any help.

Jeff


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## mikeyny (Feb 6, 2011)

I made my own baffles out of some old steel lying around the shop. Ih ad a hard time getting a good burn before. this yr I may try again. I do know one thing, your door gaskets have to be in perfect condition with no leaks in order to control the burn. Also you definitely need adequate draft. and also put in a co detector just for safety. I will be trying again in about 2 or 3 weeks when I run out of good wood. I will post my results. I read somewhere here the other day about a guy who made a basket to burn wood pellets in his boiler. It might be safer to try that instead. I may try it myself. Good luck
                                                                                                                Mike


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## Singed Eyebrows (Feb 7, 2011)

To burn coal(anthracite) you normally need a flat floor in the firebox, I don't know what your Tarm has. You need some sort of shaker grate that gently scrapes the ash from the bottom of the coal bed to allow air to rise through it. If these air passages get plugged an anthracite bed will go out. Provided the floor is flat you can weld up a rectangular box, open top & bottom & just set it on the grate & make a shaker(a sliding perforated plate will also work to scrape the bottom of the coal bed. ) As told to me by a solid fuel engineer, you don't need a lot of grate area with hard coal as it burns very hot, Randy


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## Chris Hoskin (Feb 7, 2011)

not sure what happened with the price quoting jsbruns, sorry about that.  Coal baffles are only part of making a 404 burn coal effectively.  At least as important are the shaker grates.  Please make sure you have a movable grate system in place before you spend too much time or money on coal baffles.  Based on your description of the fire going out, my guess is that you are burning with wood grates and adding coal baffles will not help with that.  Coal shaker grate kits are no longer available; we do have individual coal grates available, but not the shaker mechanism.  Hope this helps.  Chris


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## jsbruns (Feb 7, 2011)

Thanks for the reply. I do in fact have the shaker grates installed and in good working order. I don't recall exactly how many grates there are, but I'd say probably 6 or 7. Each of the grates connect to a steel spine which can be moved, in turn moving each of the grates independently. I have a 1/2" steel rod with a 90 degree bend on the end which can be inserted into a hole in the spine. The grates rock back and forth easily with a pull/push method of the rod. 

I'm pretty sure I'm all set up to burn coal, minus the baffles. From what it would appear, judging by the couple pictures I've seen it looks like the baffles basically make a wall toward the rear of the firebox, stretching left and right from each wall of the firebox and extending upwards maybe 12-14". Doesn't seem like it'd be a huge undertaking to fabricate some cast iron to sit in the position of these baffles. 

I'm not trying to sound like a cheap skate, but I'm just having a hard time swallowing the $600 price tag for a few pieces of shaped steel...

Thanks again for the help.


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## Chris Hoskin (Feb 8, 2011)

that's great news about the shaker grates!  So, I understand your reluctance about buying the cast iron baffles - since you have the shaker grates, I would suggest it is worth trying to fabricate something out of steel.  If you can work with half inch that would hold up for a long time I am sure.  The baffles will help with the burn, and I would also suggest you may need to move the shaker grates more frequently to clear ashes and clinkers and get air to the bottom of the coal fire.  Good luck with the project.  Chris


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## jsbruns (Feb 8, 2011)

I think I will give it a shot and try to fabricate something. The part list in the back of the operators manual breaks out the three individual parts that make up the coal conversion kit for the 402/502 and 404/504 models. The base plate that holds the upright baffles is listed as part #21.9066, with dimensions of 8x15". The two upright baffle sections are listed as part #06.0115, but instead of dimensions (D=) it has C=9-253. I'm assuming judging by your screen name that you're a sales rep for Tarm. Is there any way you could provide the dimensions for the upright baffles? Or at least tell me what C=9-253 is supposed to mean?

Lastly, I've searched high and low for more information on these baffles and the only thing I could come up with was the scanned PDF of the coal baffle instructions. Is there any way you could get a hold of a better picture than what's in the pdf? I assume the PDF was scanned a long time ago at a low quality, given that the couple pictures are so dark they look like silhouettes. I'm just looking for something with a little more detail so I can have a better understanding of what it is I'm building. If you're able to get your hands on any images I'd greatly appreciate it.

Thanks again for the help!


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## glhenry56 (Feb 27, 2011)

JS, 

I finally bit the bullet this year and paid for the baffles.  Yes - quite expensive, and the price has spiked since I first inquired about them a few years ago.  I had experimented with coal without them with some success, but the "flameouts" made it a pain in the backside.

I recieved the baffle kit a few days ago and installed it Friday the 25th (Feb 2011).  Removing the last grate section was a chore, but otherwise it went well.  Have had a continuous coal fire since then (nut sized Blaschak anthracite), and so far, it has gone well.   Coal is more expensive than firewood up here, and I'm not sure how I'll deal with ash disposal, but I have to say I like it so far.  Anything that keeps me from burning fuel oil is okay in my book - without getting too political, I'll just say the world would be a much better place if we Americans consumed the bountiful fuel we have here.

I'll attach some photos of my boiler and the new baffles.  Good luck with fabricating your own - if you have access to heavy plate steel, a welder, and bending equipment, I think you'll do well.  That said, I'll put in a good plug for the Tarm folks in NH.  The materials I received appeared to be well constructed, and I expect they'll last for years.

GH


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## glhenry56 (Feb 27, 2011)

A couple more photos / details about the coal baffle installation:

The bolt that attached the grate tang to the shaker mechanism came out dry.  I needed to use a cheater (iron pipe), and the bolt threads stripped.  If I choose to remove the baffles at a later date and replace the grate section, I'll have to rework the hardware.

My firebox shrunk of course, meaning I can no longer burn 16" logs.  I would have to cut the wood to about 12" (14" max) to fit properly.

I'll attach a close-up pic of the baffle support plate - a quarter inch thick piece of carbon steel with a piece of 1" angle welded on it that hold the bottoms of the baffles in place.  It also has notches cut in it to accomodate the "bump" in the boiler's separation baffles and the coal baffles' offsets.


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## jsbruns (Feb 28, 2011)

GH-

I can't thank you enough for taking the time to not only post pictures of the coal baffles, but for doing so in such detail!! Up until now I'd been working off the hand-drawn parts list found in the 500 series user manual along with a decade old coal baffle instruction low quality PDF that Tarm had scanned. That being said, my timing sucks! I spent all weekend fabricating these damn things and finished them last night! Mine don't look nearly as good as yours but they should serve their purpose at least in the short term. My steel supplier didn't have 1/2" steel so I ended up using 1/4", figuring that this could be a test run and that the 1/4" steel likely wouldn't hold up very long against the heat. I also figured I'd probably find something I should have done differently once I got them installed and a coal fire burning. The only significant difference I noticed is that the bottom corners are cut out of each of the upright baffles, allowing them to fit snugly around the lip on each of the walls inside the firebox. 

I have 3 questions for you, if you don't mind. And I assume you have the baffles installed in your furnace, so if you can just give me an approximate I'd appreciate it. 

(1) In the second picture from the top of the first post (2490_Coal Baffle Standoffs.jpg), how long does the supporting arm that rests against the back of the firebox extend outward? (explanatory picture below)

(2) In the last picture of the first post (DSC2451-.jpg) what is the angled piece sitting in front of the upright baffles? Was that part of what you received from Tarm? If so, what purpose does it serve and where is it installed? When I called Tarm I was told there were only 3 pieces that make up the coal baffle kit, 1 base plate and 2 identical upright baffle plates.

(3) How tall are the upright baffles? In the 500 series user manual (http://www.woodboilers.com/admin/uploads/public/500manual(1).pdf) parts list (item #50B), the upright baffles have "C=9-254" in their description. The base plate (item #50A) has a similar description "D=4x12", which represents its dimensions according to the parts people at Tarm. I'm not sure what the C= means, but considering the base plate has its dimensions listed in the parts list I can only assume it has something to do with measurements. The Tarm people didn't know what it meant either.

Thanks again for all the help and for taking the time to post the great pictures!

Jeff


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## glhenry56 (Mar 25, 2011)

Four weeks with the coal baffle$ from Tarm and all is well.  I let the fire die for the first time in 28 days and took a "maintenance / cleanup" day.  The baffles are in fine shape, but I wanted to get them "snugged up" better against the firebox walls.  (For some reason, it appears that the baffles "lean in" a bit toward the top, and that would allow a little of the combustion air to slip by the baffles.)  I'll attach a photo showing my fix.  It's low tech, but no big deal if it doesn't work - the coal has been burning well.

Coal ash deposits are much less of an issue than wood ash, but I have to add that my wood was seasoned for less than 6 months when I started.

I made up and installed "chain turbulators" (with thanks for the idea to Jim Batty) and will add photos of them as well.  Made them from 18" lengths of 1/2" chain.  Ran me about $30 total for materials.  After some run time, I'll weigh in on the amount of improvement I see.


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## webbie (Mar 26, 2011)

It is certainly possible to burn coal in these models without coal baffles, but the 404 has such a large firebox that it makes it a bit more difficult. 

It has to be thought through - that is, from the air in to the exhaust out...both with or without coal baffles.

First thing is that is air coming in underneath the grates can sneak out toward the rear of the stove and go right up the firetubes...without going through the coal bed....well, it would be impossible to burn hard coal.

That is solved in various ways in the boiler and coal baffle and ash pan design - however, it would seem as various in the field modifications might work as good or better. Thinking out loud here.....
1. Do not use an ash pan. 
2. remove the rear two grates.
3. Seal the area where those grates are removed with a piece of stainless steel or similar material (even piled firebrick might do) with a bend downward on it so that it turns 90 degrees and contacts the bottom of the boiler near the last grate left in. 
If this is sealed relatively well against the side and bottom of the boiler, any air entering the boiler for combustion should not be forced up through the grates.

If such an installation was used without the coal baffles, the key is to bank coal in the opposite way you usually do - that is, to bank it against the front of the boiler and have it slope down so that at the rear of the boiler it does not stack up any higher than the passageway to the firetubes.....

Maybe talking partly out my arse here, but it might work for some!


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