Harman TL 300 test

Sorry to disagree with you branchburner,but I had the Harman dealer at my house 2 times to replace the fire dome.You will not get the correct seal using old gaskets.After burning the gaskets are bonded to the fire dome and are compressed.If you put the used fire dome back in, the access cover will not come into contact with the back of the fire dome and compress the gaskets for a tight seal.A new fire dome will extend out past the back of the stove and the access cover has to be tightened down evenly to compress the gaskets.If someone takes out their fire dome and puts it back in their is a good chance of it not sealing properly. You just might have been lucky branchburner.

According to the manual you can take out the shoe to view the combustion package from the front and possibly carefully clean and inspect it from the front and not disturb the rear gaskets. At least on the 300 anyway. According to the picture in the manual there are a lot of small holes in the refractory material behind the shoe that may need to be opened/cleaned. Branchburner could confirm this as iv never taken mine out (the shoe) Also there are several different versions and models so possibly all these are not the exactly the same.

cannon said:

You will not get the correct seal using old gaskets.If someone takes out their fire dome and puts it back in their is a good chance of it not sealing properly.

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I'm not disagreeing with you about the seal, and it's a very good point. We are just in disagreement that a perfect seal is required for secondary combustion to occur. It might be a little harder to achieve or maintain your secondary burn with a bad seal, but that would be better than having no secondary combustion at all with a clogged AB.

It certainly must be the case that a perfect seal is better than an imperfect one. But if the stove is not performing well due to problems with the AB, you don't necessarily need to buy a new AB. If you clean the old one and the problems don't go away, THEN you need a new one.

I agree in general it is probably a good idea not to remove it unless you have to.

Seasoned Oak said:

According to the picture in the manual there are a lot of small holes in the refractory material behind the shoe that may need to be opened/cleaned.

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Yes, when I pulled mine out I cleaned thes out with a nail. Some were fully crusted over. As I recall, it would be hard (or impossible?) to clean these all from the front, although there is certainly some cleaning that can be done from the front.

To take out the shoe (and other firebrick/refractory in the back) to view the combustion package and carefully clean and inspect it sounds like a good once-a-year practice. Pulling this hard refractory out the front and putting it back in is not too hard, and will not disturb the rear gaskets or the seal with the AB.

cannon said:

I had the Harman dealer at my house 2 times to replace the fire dome.

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Just curious... over what period of time was this, and why did it need to be replaced? How much ash/crust did the old units have, and were they clogged?

In case anyone wonders what a clogged AB looks like, a picture is worth a thousand words:

http://woodchuckcanuck.com/wp-content/uploads/2011/12/20130930-harmonwoodstove1.jpg

Yup, same as the one pictured in the manual. Only clogged.

branchburner said:

Just curious... over what period of time was this, and why did it need to be replaced? How much ash/crust did the old units have, and were they clogged?

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I was actually on my 5th fire dome in less than 2 seasons.The fire dome didn't want to light off right and the wood stack would burn across the top of the wood instead of from the bottom.When the dealer decided to replace the damper door assembly because they had problems with some of them warping,they found that the gasket for the damper door assembly was never installed from the factory.So the stove was just sucking air across the top of the wood stack.

cannon said:

I was actually on my 5th fire dome in less than 2 seasons.The fire dome didn't want to light off right and the wood stack would burn across the top of the wood instead of from the bottom.When the dealer decided to replace the damper door assembly because they had problems with some of them warping,they found that the gasket for the damper door assembly was never installed from the factory.So the stove was just sucking air across the top of the wood stack.

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you must be kidding? If not, i would NEVER go back there. That is sooooo simple. To replace the firedome 4 times is just laughable, especially since you can see that gasket area when you open the top door.

I look at mine(AB holes) when reloading,,,all holes are clear so far. I will vacumn this week end as i may let the fire go out when it hits 50 this week.

cannon said:

When the dealer decided to replace the damper door assembly because they had problems with some of them warping,they found that the gasket for the damper door assembly was never installed from the factory.So the stove was just sucking air across the top of the wood stack.

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No doubt some of them warped due to overfiring. Iv found once the stove heats up sufficiently you really must close that damper door as the door and everything just above it keeps getting hotter and hotter. Someone not paying attention or inadvertently leaving it open too long with a high air setting could easily cause damage after awhile.

branchburner said:

In case anyone wonders what a clogged AB looks like, a picture is worth a thousand words:

http://woodchuckcanuck.com/wp-content/uploads/2011/12/20130930-harmonwoodstove1.jpg

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Looks like the opening along the bottom is almost completely clogged.

For me I am on my 2nd AB, what damaged my first one was the center Harman brick broke exposing the AB to a full wood load. This caused damage to the top half of the AB.

razerface said:

you must be kidding? If not, i would NEVER go back there. That is sooooo simple. To replace the firedome 4 times is just laughable, especially since you can see that gasket area when you open the top door.

I look at mine(AB holes) when reloading,,,all holes are clear so far. I will vacumn this week end as i may let the fire go out when it hits 50 this week.

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It wasn't the damper door gasket,it was the gasket for the damper door assembly. The damper door assembly is bolted to the top of the stove from the inside,the stove guy didn't realize it was missing until he removed the assembly.After he fixed it I sold the stove.

cannon said:

It wasn't the damper door gasket,it was the gasket for the damper door assembly. The damper door assembly is bolted to the top of the stove from the inside,the stove guy didn't realize it was missing until he removed the assembly.After he fixed it I sold the stove.

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Too bad you had a bad experience with this stove. Its a real heat machine when its put together right and operated correctly. My harman process wood smoke so much better than my burn tube stoves and the heat is much more even over the entire burn cycle. Only thing better i would think would be a cat stove.

cannon said:

It wasn't the damper door gasket,it was the gasket for the damper door assembly. The damper door assembly is bolted to the top of the stove from the inside,the stove guy didn't realize it was missing until he removed the assembly.After he fixed it I sold the stove.

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that is different, i missed the word "assembly",, thanks for correcting me.

MishMouse said:

For me I am on my 2nd AB, what damaged my first one was the center Harman brick broke exposing the AB to a full wood load. This caused damage to the top half of the AB.

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been meaning to ask you about that. How did it damage the AB? Was there direct contact? I wouldn't think the heat would hurt it.

razerface said:

been meaning to ask you about that. How did it damage the AB? Was there direct contact? I wouldn't think the heat would hurt it.

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I do not know if the wood made direct contact with the AB since it happen when I was at work. But, according to the dealer if the AB gets exposed to direct heat it could get damaged. Since the damage was where it got exposed it does look like the direct heat caused it. By exposing the AB the heat path through the AB was not as it was designed, which caused it to degrade. Now, would it of happened if the AB wasn't ~5 years old at time, maybe not. Got, the stove in April 2008.

Did the dealer offer up any temp range that would damage it? I have had 2000+ deg recorded on my digital, inside the flu, which is way after the AB on the way out the chim. It has to be hotter going thru the AB then it is at that digital probe.

From what i understand heat will not damage the material. THats why they use it as opposed to steel . It is fragile so any direct contact with wood or ash may damage it, but it is built for high heat same as the baffle boards in the burn tube stoves which are also fragile.

Seasoned Oak said:

From what i understand heat will not damage the material. THats why they use it as opposed to steel . It is fragile so any direct contact with wood or ash may damage it, but it is built for high heat same as the baffle boards in the burn tube stoves which are also fragile.

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salesman told me that it used to be a cast iron shoe in front of the AB, but people were melting it!

razerface said:

salesman told me that it used to be a cast iron shoe in front of the AB, but people were melting it!

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IT was cracking from the heat. Gets pretty hot down there.

MishMouse said:

I do not know if the wood made direct contact with the AB since it happen when I was at work. But, according to the dealer if the AB gets exposed to direct heat it could get damaged. Since the damage was where it got exposed it does look like the direct heat caused it. By exposing the AB the heat path through the AB was not as it was designed, which caused it to degrade. Now, would it of happened if the AB wasn't ~5 years old at time, maybe not. Got, the stove in April 2008.

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Sounds like the dealer was trying to save his can, the only way the AB gets damaged is by direct contact. Heat will not damage it, and you cant physically puncture it unless the ceramic bricks are not in the right place or cracked exposing the fragile refractory material.

Nice stove! I got a harman too and love it!! looks like a great location for getting the house nice and toasty.