How do I know if the afterburner is working properly? Harman TL200

[Josh Hufford]

Yesterday I installed the glass for the afterburner viewport in my stove, it had been missing since I got the stove, (see this thread https://www.hearth.com/talk/threads/harman-tl200-afterburner-glass-missing.101751/ )

I'm not seeing a big difference in how the stove operates, and I still see a lot of smoke coming out of the chimney. I've never owned a stove with an afterburner so I don't really know what to expect. So I'm asking others who have similar stoves what to expect. And how much smoke should I see coming out of my chimney? Can something else be wrong with the afterburner?

Thanks!

 

[Josh Hufford]

Well for a little while today I was able to see an orange glow and a few flames dancing around behind the glass. Is that what its supposed to do when working? It only lasted for about 30 minutes.

 

[MishMouse]

In order to get the AB to work you must have the following:
1) adaquate draft
2) a good coal base
3) must get the flue hot enough to maintain a strong draft
When the AB kicks off you should hear a roar of the AB working.
Then once it settles down you should see occasional poofs of fire inside of the stove.
There should be no visiable smoke when the AB is working properly.
I do not own the TL200 I own a TL300 but the concept should be similiar.
I am thinking yes when it is working properly you should be able to see some flames dancing behind the glass.

 

[Josh Hufford]

When you say " AB kicks off" off as in off and running or as in shuts off? I've only heard the roar once, how long does the roar usually last on yours? When you say "poofs of fire inside the stove" could that also be described as small flames that seem to dance around in the stove not directly coming off the wood and sometimes flame near the window where the combustion air is introduced into the stove? The TL300 has a lower emission rating than the TL200 so maybe some smoke is still normal. Thanks a lot for your reply, the manual doesn't do a very good job of describing how it works and what to expect.

 

[MishMouse]

The roar sound typically only lasts around 5-15 mins before it settles down to more of a soft roar. Yes, when running you will see flames dance around the stove that does not come directly off the wood. Do a search on this site on TL200 and variations of TL200. I know there is a couple of members on here or were on here in the past that own the TL-200. What it sounds like is you are not getting the stove hot enough for the AB to kick in. What is your stove temps/pipe temps?

 

[Josh Hufford]

I only have one thermometer on my pipe about 1 foot up above the stove, I don't have one for the stove so I guess I should get one. I usually don't close the bypass damper until its gets above 400, sometimes higher if I have time to keep a close eye on it. If I let it burn with the bypass damper open and the air control open the pipe temp can get really hot really quick. Once I close the bypass damper the pipe temp usually drops down to between 200-300. I did do some searching on the forum for this stove but didn't come up with a lot but I'll try again. Thanks!

 

[branchburner]

Not sure if this will work the same on your stove, but on my Oakwood I have a thermometer on the side of the rear burn chamber. When the AB is engaged, the surface temp will rise to 400-800F. If the AB does not kick in, the temp will not budge at all, and stay in the 200-300 range.

This does not always have a direct relationship to the stove top or flue temp, but the rear-side temp will generally stay high even when I bring the air control back from 2/3 to 1/3 open - whereas the flue temp will always drop when I do this. If I bring the air down too far or too fast, the AB may stall and the temp will drop back to the 200-300 range, meaning I have to open the bypass for a few minutes.

You should have no smoke with the AB doing its thing. The initial roar will soften to a very gentle and sometimes barely audible "whoosh" on my stove. I rely greatly on the rear-side thermometer, and now pay less attention to flue temp (only when bypass is open, to avoid excess flue temps) and pay no attention to stove top temps.

 

[branchburner]

Also consider, your stove is not new so the afterburner part itself may be compromised - either clogged with ash or degraded with age. Is the stove vented into a 6" flue, or something larger? Is your wood well-seasoned? How large are the splits? Try mixing in some very dry hardwood pallet scraps with your cordwood to get a quicker, hotter and deeper coal bed, and if you can't get it to burn smoke-free you may have an AB issue - but give it some time and experimentation first, as these stoves can have a bit of a learning curve.

 

[Josh Hufford]

Thanks, that is great advice. How long after you close the bypass damper do you see the temp on the back rise? My flue comes out of the stove straight up about 3 ft, does a 90 and then goes through the wall into a brick chimney that has a 6" liner. It goes into a liner with at Tee, the installer used a Tee because the chimney has a cleanout at the bottom, and this way I could run a brush down the liner and just remove any buildup at the cleanout. From the Tee I haven't measured but I'm guessing its probably about 15ft to the top? I have seen and heard the afterburner working, but it does take the right conditions to get it working. I'm not convinced there isn't something still wrong with it but for now the stove is heating our house just fine. As long as I don't have any major problems this spring when the burning season is over I'll take it all apart and inspect everything more carefully and see if I see anything wrong with the AB.

 

[branchburner]

Temps should rise in the back in just a few minutes when the AB kicks in.

Does the tee have a cap on the bottom, or is it open?

 

[Josh Hufford]

I'm pretty sure its open.

 

[mellow]

That could be affecting your draft, it really needs to be a sealed system so cold air does not enter and disrupt the warming which keeps your draft going

 

[Josh Hufford]

Hmmmm, I was wondering if that was affecting my draft. I don't see any way to easily plug it, and it would be nice to make use of it when cleaning. Any ideas?

 

[mellow]

If I had a downdraft stove I would be using an insulated liner for sure, anything that throws off the draft will make that stove harder to burn.

If it was me I would pull the liner up and fix that T snout and insulate that liner and put in some 45's instead of a 90 in the singlewall.

 

[Josh Hufford]

How do you insulate the liner? It just pulls straight out? I'm not sure I'd have room for a 45, I'll try and post some pics of my setup.

 

[mellow]

(broken link removed to http://www.rockfordchimneysupply.com/insulation_kits.php) <---- has videos on how to insulate

(broken link removed to http://www.rockfordchimneysupply.com/chimney-liner-kit.php) <--- that will give you an idea of all the components that go into your install

The liner once the snout is disconnected from the single wall should pull straight up and out, it is connected to the top plate as well.

 

[Josh Hufford]

Thanks for that good info. I wonder if there is any way I could get a cap up to the bottom of the Tee through the cleanout and get it to attach to the bottom of the Tee without having to pull the whole thing out.

 

[mellow]

The only thing I could think of is to drop a string down from the top of the liner, once you get it through the clean out on the bottom attach a strong magnet to it then put the cap on the magnet centered then pull the string up and see if you can get it to attach? If you get it to attach you should be able to yank on it and get the magnet to come up.

 

[Josh Hufford]

That is a great idea!. Ok where do I order a 6" cap for my Tee?

 

[mellow]

Try calling rockford and see if they have just the caps they can sell you.

 

[mellow]

Another thought is to detach the single wall and run the string down that way, might be able to get your hand in there to help attach the cap and not go up on the roof.

 

[Josh Hufford]

Good idea as well, thanks a lot for the help. I'll probably try the cap first and see if my draft improves. I've never been able to load from the top without getting a little smoke, usually after I start putting wood in. I've never had a top loading/downdraft stove so I don't know what is normal or not. If that doesn't help enough I'll look into insulating it.

 

[branchburner]

If the tee is uncapped, I'll bet that is diluting your draft and affecting performance of the whole system.

Could't you just extend the pipe down from the tee by adding a length of pipe, so that the pipe terminates within reach of the cleanout door? That would still allow cleaning as desired, but also allow you to reach in and put a cap on the pipe extension.

 

[Josh Hufford]

If the tee is uncapped, I'll bet that is diluting your draft and affecting performance of the whole system.

Could't you just extend the pipe down from the tee by adding a length of pipe, so that the pipe terminates within reach of the cleanout door? That would still allow cleaning as desired, but also allow you to reach in and put a cap on the pipe extension.

I could but I know I'd have to pull the whole liner out to do that. I'm getting a cap ordered from Rockford, and I'll try the string and magnet method either this summer when I clean the liner out or maybe if we get a warm spell this winter. If that doesn't work then I'll pull the liner out, extending the pipe is a good idea. The stove is still doing good, but I pretty sure its not working at 100%.