Advice on Harmon TL300 setup please

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anno Domini

New Member
Jan 15, 2024
8
Mi
Hello and thank you for this forum as ive learned quite a bit of information here.

Setup includes professionally installed Harman TL 300 with double walled 15ish ft chimney. Using dry wood, mostly oak at this point. Large, drafty ranch style house. Using Imperial magnetic temp gauge.

Ive looked at key damper threads and, while helpful, havent addressed my issue. The stove is a champ (with its share of faults) throughout the majority of the burning season. However, when its quite cold i.e. below zero, i would like to slightly throttle the stove with a key damper in bypass mode: with a full load in bypass mode it tends to "overfire" (700+ indicated on gauge) within 10ish min even with air intake at lowest setting. I then close stove damper and immediately open air intake to highest setting. After again 10ish min it burns decently enough to prevent creasote buildup but not much heat.

I world like to install a key damper that would be open 90% of the burning season, but would adjust as neccassary on frigid days: keep stove loaded to gills in bypass, air intake continuously at lowest setting, adjust key damper as neccesary to maintain 500 ish degrre-as-indicated. Always fully open when stove damper is closed.

1 - plausible and\or good idea? Does it make sense?
2 - are there key dampers that are of superior quality? Should i install myself or get or get one already fitted to 6inch length of pipe?

Sorry if this has been addressed and thank you for reading.
 
Hello and thank you for this forum as ive learned quite a bit of information here.

Setup includes professionally installed Harman TL 300 with double walled 15ish ft chimney. Using dry wood, mostly oak at this point. Large, drafty ranch style house. Using Imperial magnetic temp gauge.

Ive looked at key damper threads and, while helpful, havent addressed my issue. The stove is a champ (with its share of faults) throughout the majority of the burning season. However, when its quite cold i.e. below zero, i would like to slightly throttle the stove with a key damper in bypass mode: with a full load in bypass mode it tends to "overfire" (700+ indicated on gauge) within 10ish min even with air intake at lowest setting. I then close stove damper and immediately open air intake to highest setting. After again 10ish min it burns decently enough to prevent creasote buildup but not much heat.

I world like to install a key damper that would be open 90% of the burning season, but would adjust as neccassary on frigid days: keep stove loaded to gills in bypass, air intake continuously at lowest setting, adjust key damper as neccesary to maintain 500 ish degrre-as-indicated. Always fully open when stove damper is closed.

1 - plausible and\or good idea? Does it make sense?
2 - are there key dampers that are of superior quality? Should i install myself or get or get one already fitted to 6inch length of pipe?

Sorry if this has been addressed and thank you for reading.
700 where?
 
On imperial flue gauge.
So your seeing 700 on the surface of single wall pipe. That is extremely high have you checked for air leaks? Something sounds really off with that
 
The OP may find this information helpful, or not, although not directly relevant to his questions and comments.
 
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It’s too bad, that review. I nearly bought one of these because the overall design was good. That is, the overall concept. Too bad the inner design is so high maintenance. They’re food stoves if you maintain them properly, which comes as a high cost to the end user.

Be sure and clean behind that refractory and deeper behind it…which is the biggest fault of the stoves and dealers…not informing users this area needs such deep cleaning, and clean it often. Do that and the stove will function fine.

Love the top load and grill features. Jotul made a similar style loading and grilling stove and discontinued it, Jotul F TL series, I believe.
 
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I will certainly check for air leaks, i appreciate you bringing that to my attention.

Thanks also for posting that link to the 5 year review though it was already bookmarked :) We cleaned afterburner and behind it prior to this season, seems to be running smoother with damper closed, just need to brush it every morning.
 
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Reactions: Hoytman
It’s too bad, that review. I nearly bought one of these because the overall design was good. That is, the overall concept. Too bad the inner design is so high maintenance. They’re food stoves if you maintain them properly, which comes as a high cost to the end user.

Be sure and clean behind that refractory and deeper behind it…which is the biggest fault of the stoves and dealers…not informing users this area needs such deep cleaning, and clean it often. Do that and the stove will function fine.

Love the top load and grill features. Jotul made a similar style loading and grilling stove and discontinued it, Jotul F TL series, I believe.
And that jotul was just as much of a pos as the Harmans. There has never been a down draft stove that didn't suffer from reliability issues.
 
And that jotul was just as much of a pos as the Harmans. There has never been a down draft stove that didn't suffer from reliability issues.
Hadn’t heard or read of any issues with the Jotul TL Rangely (not that there wasn’t any complaints), but much if what I’ve read of other down draft designs has been plagued with problems.