TLC 2000 - Controling the Burn

We have a new TLC 2000, and have been running it about 5 days 24/7, burning stove coal sized sub-bit as it's what's available here. It's heating a 2700 sq ft (2 stories and walkout basement) 80 year old home. We're only getting 12/14 hour burn times on two 5 gallon buckets of coal. This is with the unit damper slider generally between notches 1-2 for running, and 3-4 for reloading (usually about 20 minutes).

The unit is located in the basement, has a 6' run of stove pipe with two 45 degree and one 90 degree fitting to enter into the chimney, which connect to a 24' run of SS flexible 6" liner to the top of the the chimney cap.

Even with the TLC slider damper fully closed, it can go through some coal and can give some yellow flame at times. I've just installed a Fields Controls B-24 barometric damper, but don't have a manometer yet. It seems to give a more even burn as the coals 'look right' as opposed to before, but even setting the damper weight to the closest setting against the flapper (allowing the barometric damper to open the easiest) and then fully closing the damper slider on the TLC, it will open the barometric damper about 3/4s but still burn at a pretty healthy rate in the firebox.

I have checked and double checked the door and window gaskets using the paper test, and the seal on the ash door and top loading port seem secure. The wood burning control dampers on the upper left and right of the stove are closed.

I'm open to ideas and appreciate your time.

Welcome to the forum Kielanders!

It's the sub-bit coal that your burning in my estimation. You are going to have yellow flames and smoke with sub-bit coal. It's only a step above lignite which itself is a step above peat.

You stove was designed to burn anthracite; to burn bituminous you need a lot more secondary air.

Stove size coal also breathes a lot easier than smaller sizes making it harder to control.

Because the bit coal contains a lot more gas it has a similar problem as wood stoves do in igniting a large amount of gas at once which drives up stack temperatures. Antique stoves intended for bit coal have special secondary air fixtures to aid in burning.

Thanks for your replies everyone.

I'll ask a question, not to be argumentative or question your responses, I've plenty of experience with wood stoves, but coal is a different animal.

Shouldn't I be the one that determines the rate of the burn via the damper mechanism?

On a quality stove like this, it was my impression prior to buying, that it was an essentially an 'air tight' stove - that fully dampered, it should kill the fire - and that somewhere between fully dampered and fully open (regardless of chimney overdrafting), I should be able to dictate the rate of burn based on the temperature I desire and the amount of fuel I'm willing to burn.

Sub-Bit is all that's available here in quantity for 1000 miles ($80/Ton), unless I want to burn bagged imported anthracite which would be insanely expensive and would have to travel 140 miles to purchase.

Regardless of the type of coal, all fossil fuels need oxygen, so it seems to me that my stove or system isn't tight enough to give me control over the burn.

I was considering disassembling the lower damper on the TLC to see if there is a way to incorporate a high temperature fabric gasket into the assembly to further restrict airflow. Also I'm considering the installation of a wind directional chimney cap, although, I'm not sure if that will help reduce the draft.

Warranty issues aside, I don't like having to do that on a new stove whose key selling point for me was a 60 hour burn time.

My rational was that I assumed in real-world conditions (i.e. my basement), I would be able to refine my daily process to stove maintenance once every 24 hours. I didn't think that was too ambitious.

Again, these are my thoughts being new to coal stoves, not saying I'm right - just asking for your thoughts and corrections.

Thanks everyone - this is a great forum.

With a low BTU coal and decent heating load you won't be able to tend your stove once/24hours. A 60 hour burn-time? it just won't happen, so forget about that. If you want that, go with a bit stoker and pay $$$.

you're going to have yellow flames with your coal because of the higher hydrocarbon content, most of what you read here will not be applicable to your situation because most of these folks are burning anthracite, not bit or sub bit. If you want to learn more about bit/sub-bit read the threads in the bituminous forum. Bituminous is NOT like anthracite, with subbit/bit the largest sizes of coal burn the slowest and have the longest most controllable burn.

I am not familiar with that particular stove, but subbit coal, like wood, will try very hard to burn fast unless the air can be carefully controlled. If you have trouble closing down the air, there's either a problem with that particular stove or it's part of it's design to pass epa emissions requirements with wood. I will let you know that trying to get extended burntimes by loading large amounts of coal in the stove and then cutting way back on the air and eliminating flames is an excellent way to get a large back-puff and you will end up covering your home with soot thanks to your new barometric damper.

2 X 5Gal. buckets for 12/14 Hrs! And at the present time! Imagine in the coldest time ! Something is not correct on the stove. Do you let some ash on the grates? Did you checked if the primary air control works correctly and close as supposed? Maybe the ""by-pass"" wood systm doesn't operates in the good way???

I own a TLC-2000. I just looked at the manual, and it does say that results with bit will vary because of inconsistencey in the coal. I also believe that there is an "air-wash system" built into the design of the stove to help keep the glass clean. That may be where you are getting unwanted air.
I am very pleased with the stove. I'm entering my third season with it. I can easily get 24 hr. burns; although I prefer to tend it every 12 hrs. Last winter we went to visit my son in New Hampshire. I loaded it to the hilt late Friday and set it slightly higher than just idling. We returned Sunday afternoon and found it just the same as I left it. Grant you, I was a little more careful with shake-down and reload.
But I don't burn bit and know little of it's burning charactoristics. But it does mention it as a fuel with exception.
I would Definitely get a manometer to set your dampener with it. If it is not absolutely air-tight that will help with weakening the draw on the stove.

I would not use a baro. That is just asking for a soot problem.

not a coal burner here, mostly a lurker, but love reading about the coal stoves here (secretly wish I had one, yes...)

Just wanted to toss an idea out there though--what about trying to open up the wood secondary air sliders on that stove? if that air passes through higher up, maybe it'll satisfy some of the draft so less air comes through the grate and ash-pan damper? might also burn the subbit cleaner?

also I guess you know with wood, heavy primary air tends to cause you to eat through wood really fast, damping primary air and allowing plenty of secondary air slows it down (but burns it cleaner)... if your draft is that awesome you should consider yourself lucky!

Berlin, I've had 3 fairly interesting puff-backs so far while I've worked on my learning curve with stove maintenance the past week - they do get your attention. Your point about puff-backs through the baro-damper is a good one and concerns me a bit. Thanks for your thoughts about Bit and Sub-Bit.

Body Hammer, your point about possible infiltration from the air wash system is a good one. I'm going to take some time looking at the exploded diagram for the stove in the parts page more closely to try and understand the stove better.

Markviii, the barometric damper was recommended to us by Harman factory support on Thursday. I need to order a manometer to set it precisely - which I will do. Considering the 3 puff-backs I've already had - I am glad the stove is in the basement, the baro-damper still may need to be uninstalled longer term.

Spirilis, I'll experiment with the wood sliders. Thanks for the thoughts on primary and secondary air control.

I just found a spec sheet on the coal from the mine that our coal comes; it is in fact a low grade Sub-Bit with a high moisture and volatile content - sold mainly to Asian power plants. That being the case, and while I might be able to tweek my install a little, it may just be a matter of making the best of what I have to work with and burn.

That being said, coal stoves are fun - this guy definitely has his own personality.

Does anyone know if a wind directional chimney cap is a possible way to lower/manage a strong draft, or will it only serve to prevent negative draft conditions and not lessen strong positive drafts?

I think you are correct in your assessment. With that poor quality of coal it's not must different that burning soft wood, Best of luck to you.

SteveZee wrote:I think you are correct in your assessment. With that poor quality of coal it's not must different that burning soft wood, Best of luck to you.

Thanks SteveZee, your original comment got my wife to do some searching and find the spec sheet on our coal.

steve, that "poor quality" coal is going to be a hell of a lot better than wood, soft or not. even low BTU subbit has a much higher energy density than any wood.

Try a combination of 1/3 primary air to 2/3 secondary air. The coal needs most of the air over the fire until all of the yellow flames go away, then you might try to reverse the draft combination. I know Harman recommended a Barometric Damper, but; for your application I would seriously think about removing it.