Chimney liner height and creosote issue

  • Active since 1995, Hearth.com is THE place on the internet for free information and advice about wood stoves, pellet stoves and other energy saving equipment.

    We strive to provide opinions, articles, discussions and history related to Hearth Products and in a more general sense, energy issues.

    We promote the EFFICIENT, RESPONSIBLE, CLEAN and SAFE use of all fuels, whether renewable or fossil.

The Brit

Member
Dec 3, 2018
48
BC, Canada
Can anyone please give their experience feedback here.

Blaze King Ashford 30, installed brand new, running for three months now, elevation about 3000ft, chimney liner double wall going up a wood chimney chase to spec, floor to chimney liner top height 17 - 18ft, 1 elbow, 1 "T", 32" horizontal run, split wood moisture 15 - 19%, Kiln dried wood 8%, split wood also at 12%. Never mix the wood by experiment. I have tried placement of wood in NSEW directions, smaller loading, full loading.

Have to always operate the stove at about 3/4 - 7/8 open otherwise the unit will cool off too quick. Get a lot of creosote on the glass and burning on high only removes the surface creosote. Keeping it on high will cook the house (1750sq.ft) upper level.

Does anyone have an experienced opinion that increasing the flue height by even 3ft would give me a better draft, and therefore result in better damper control and perhaps less creosote on the glass. My guess is a little more draft will help to keep the glass cleaner to some extent.

By the way, I inspected the flue and it is absolutely clean, NO creosote at all, only a light dusting of grey ash.

Many thanks guys
Andy
 
Can anyone please give their experience feedback here.

Blaze King Ashford 30, installed brand new, running for three months now, elevation about 3000ft, chimney liner double wall going up a wood chimney chase to spec, floor to chimney liner top height 17 - 18ft, 1 elbow, 1 "T", 32" horizontal run, split wood moisture 15 - 19%, Kiln dried wood 8%, split wood also at 12%. Never mix the wood by experiment. I have tried placement of wood in NSEW directions, smaller loading, full loading.

Have to always operate the stove at about 3/4 - 7/8 open otherwise the unit will cool off too quick. Get a lot of creosote on the glass and burning on high only removes the surface creosote. Keeping it on high will cook the house (1750sq.ft) upper level.

Does anyone have an experienced opinion that increasing the flue height by even 3ft would give me a better draft, and therefore result in better damper control and perhaps less creosote on the glass. My guess is a little more draft will help to keep the glass cleaner to some extent.

By the way, I inspected the flue and it is absolutely clean, NO creosote at all, only a light dusting of grey ash.

Many thanks guys
Andy
Creosote in the box and on the glass is perfectly normal with a cat stove shut it back more
 
otherwise the unit will cool off too quick

How are you determining that or what is your measure of that?

According to the manufacture's guide I should be at near to 25ft plus, which is ludicrous. The WETT standard is to measure from the floor level.
All I get from the installer is that they have installed hundreds of these stoves and I have overly humid wood. NOT so! I have used wood as low as 5% and if I burn on high, then it will keep the creosote to a minimal level of course.
The BIG issue is I CANNOT dial the cat down below about 3/4 otherwise the glass craps up again and the heat dies off. To me it seems inadequate draft, also indicated my some smoke coming out of the door.
I don't know if this is helpful, but in the -25C weather for example, to get any heat output I have to run the unit at 7/8 open, which of course will go through wood very quickly.
 
If I shut it back more the fire will go out.
Yes but will the cat still be active? Many times cat stoves will run with no active flames in the box. That is perfectly fine as long as the cat stays active it is working properly
 
Also how are you measuring the moisture content of your wood?
 
I wasn't sure from your post - how high is the top of your chimney from the top of the stove? I don't think the manual refers to measurements from the floor.
 
Go by cat temp not flame. Wood smoldering creates smoke which is what the cat burns. Often I have no flame in the box and 1000+ cat temps so i know she is cruising along just fine.
 
Yes but will the cat still be active? Many times cat stoves will run with no active flames in the box. That is perfectly fine as long as the cat stays active it is working properly

To be sure, if I dial the cat down to about 1/2 - 5/8 setting the temp will drop and the cat will not be in the active zone. It is stated that I should be able to dial the cat right down and still be in the active zone.

I am also wondering if the air intake is an issue. The 4" pipe comes in through straight then at the back of the stove it has a saddle bend before it enter the underside of the stove. This to be represents two 90 degree bends as it were. Is it possible that this is also restricting the draw of air couple with a potentially short flue height?
 
I wasn't sure from your post - how high is the top of your chimney from the top of the stove? I don't think the manual refers to measurements from the floor.

Your correct, the manual does not say measure from the floor, but the WETT standard apparently stipulates to measure from the floor. I think this only adds conflict to the calculations of flue height; what is truly necessary for a good draw.
My height from stove top to chimney top is about 14' 4". Too bloody short if you ask me. And remember I am at 3000 ft elevation.
 
Go by cat temp not flame. Wood smoldering creates smoke which is what the cat burns. Often I have no flame in the box and 1000+ cat temps so i know she is cruising along just fine.

Wow, the only way I can get a 1000 degrees is to run it at fully open all the time, which will cook the house because the wood is really burning fearsly with flames.
 
To be sure, if I dial the cat down to about 1/2 - 5/8 setting the temp will drop and the cat will not be in the active zone. It is stated that I should be able to dial the cat right down and still be in the active zone.

I am also wondering if the air intake is an issue. The 4" pipe comes in through straight then at the back of the stove it has a saddle bend before it enter the underside of the stove. This to be represents two 90 degree bends as it were. Is it possible that this is also restricting the draw of air couple with a potentially short flue height?
I am not sure where it states you will be able to turn it all the way down but that is not nessecarily true. Also if the fan is on it will make the cat probe read low
 
(A pic of the install might help...)

Hope these photos help. Note the air intake pipe has a saddle bend in it, not just one elbow.

20181222_124136.jpg IMG_5532.JPG IMG_5533.JPG
 
I am not sure where it states you will be able to turn it all the way down but that is not nessecarily true. Also if the fan is on it will make the cat probe read low

The owner's manual mentions it. I also chatted with Blaze King and they said I should be able to dial it all the way back. Also I do not have a fan installed on the unit.
I appreciate your feedback.......this is a pain in the butt my friend.
 
The owner's manual mentions it. I also chatted with Blaze King and they said I should be able to dial it all the way back. Also I do not have a fan installed on the unit.
I appreciate your feedback.......this is a pain in the butt my friend.
Well I can tell you I can't turn my princess all the way back and from talking to people here most can't unless they are running 25' + chimneys.

And it's a cat stove if you run it shut back the glass won't stay clean.
 
Your correct, the manual does not say measure from the floor, but the WETT standard apparently stipulates to measure from the floor. I think this only adds conflict to the calculations of flue height; what is truly necessary for a good draw.
My height from stove top to chimney top is about 14' 4". Too bloody short if you ask me. And remember I am at 3000 ft elevation.

The copy of the manual I found on line said minimum 15' from top of stove to chimney cap, in the spec section on page 5. That's before adding the extra required for elbows, horizontal sections etc..

So ya - you are quite likely too short.
 
Well I can tell you I can't turn my princess all the way back and from talking to people here most can't unless they are running 25' + chimneys.

And it's a cat stove if you run it shut back the glass won't stay clean.

Hi again, that's exactly what I think too. Yes in reality I need a 25 foot run. It's funny the renowned installer will not make any comment on that and INSISTS I am to blame..........hmmmm. Where is one to go from here when you have complied to ALL of there demands?
 
I am using a recommended 4 prong perpetrator meter probe. Measuring split wood from both ends of split and in the middle as recommended.
By both ends do you mean end grain or face near the end. Also is the face freshly split?
 
The copy of the manual I found on line said minimum 15' from top of stove to chimney cap, in the spec section on page 5. That's before adding the extra required for elbows, horizontal sections etc..

So ya - you are quite likely too short.

Thanks man, that's what I feel. The installer is FINALLY coming out here today to do a full test. It will be interesting to see what he has to say. I will keep you all posted.
Big thanks.