Hot interior wall along chimney

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valleyfire

Member
Sep 10, 2018
20
Massachusetts
We have a Pacific Energy Alderlea T4 vented through a 35' flexible metal liner that runs through a brick chimney in the exact center of our house. On the first floor, each side of the chimney (covered in plaster) faces a large room. On the second floor, one of the sides of the chimney (again, covered in plaster) forms one wall of a closet that is usually closed, and which is packed full of clothes.

We do not run the stove often or usually for more than 4 hours at a time. A week ago we ran it for 15 hours straight (always in the safe temperature range, according to the thermometer on their stove pipe). After the fire had started to cool for an hour or two, we opened the closet and discovered that the chimney wall was quite warm. I am not sure of the temperature - it was not as hot as our hydronic cast iron radiators get, but if it had been any hotter I couldn't have kept my hand on it for more than a minute. The other sides of the chimney on the second floor were not noticeably warm, nor were the chimney walls on the first floor.

After we emptied the closet and kept the door open, the hot wall cooled almost to room temperature in an hour or two.

How concerned should I be? My plan was to not run the stove against this winter, and have the liner replaced with an insulated liner in the off season.
 

bholler

Chimney sweep
Staff member
Jan 14, 2014
25,497
central pa
We have a Pacific Energy Alderlea T4 vented through a 35' flexible metal liner that runs through a brick chimney in the exact center of our house. On the first floor, each side of the chimney (covered in plaster) faces a large room. On the second floor, one of the sides of the chimney (again, covered in plaster) forms one wall of a closet that is usually closed, and which is packed full of clothes.

We do not run the stove often or usually for more than 4 hours at a time. A week ago we ran it for 15 hours straight (always in the safe temperature range, according to the thermometer on their stove pipe). After the fire had started to cool for an hour or two, we opened the closet and discovered that the chimney wall was quite warm. I am not sure of the temperature - it was not as hot as our hydronic cast iron radiators get, but if it had been any hotter I couldn't have kept my hand on it for more than a minute. The other sides of the chimney on the second floor were not noticeably warm, nor were the chimney walls on the first floor.

After we emptied the closet and kept the door open, the hot wall cooled almost to room temperature in an hour or two.

How concerned should I be? My plan was to not run the stove against this winter, and have the liner replaced with an insulated liner in the off season.
That is why insulated liners are important who knows what condition the wood touching that old chimney is in
 

valleyfire

Member
Sep 10, 2018
20
Massachusetts
That is why insulated liners are important who knows what condition the wood touching that old chimney is in
Thanks. I wish I had known about them when we got the stove installed. Are they all pretty much equivalent? I assume we will have to keep the same brand so it connects with the thimble.
 

bholler

Chimney sweep
Staff member
Jan 14, 2014
25,497
central pa
Thanks. I wish I had known about them when we got the stove installed. Are they all pretty much equivalent? I assume we will have to keep the same brand so it connects with the thimble.
You could just insulate your liner
 

valleyfire

Member
Sep 10, 2018
20
Massachusetts
You could just insulate your liner
Do you mean install insulation around the existing liner in situ? What material?

The chimney slopes slightly in the attic so my worry is there is no way to make sure the existing liner doesn't touch the brick somewhere - it is almost guaranteed not to be perfectly centered.
 

bholler

Chimney sweep
Staff member
Jan 14, 2014
25,497
central pa
Do you mean install insulation around the existing liner in situ? What material?

The chimney slopes slightly in the attic so my worry is there is no way to make sure the existing liner doesn't touch the brick somewhere - it is almost guaranteed not to be perfectly centered.
Yes pull the liner wrap it with liner insulation
 
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valleyfire

Member
Sep 10, 2018
20
Massachusetts
That is why insulated liners are important who knows what condition the wood touching that old chimney is in
Thanks. I wish I had known about them when we got the stove installed. Are they all pretty much equivalent? I assume we will have to keep the same brand so it connects with the thimble
Yes pull the liner wrap it with liner insulation
Thanks! I didn't realize that was an option. Much cheaper than a new, pre-insulated, liner.
 
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begreen

Mooderator
Staff member
Nov 18, 2005
89,580
South Puget Sound, WA
An insulated liner is good and required by code for most installations. As for the wall temp, if you could hold your hand on the wall for 30 seconds then it was in a safe temp range and below 125º.

How is the T4 behaving with that tall liner? Do you have a damper in the flue or a thermometer? It could be that a lot of the heat is going up the liner due to too strong draft. It wouldn't surprise me if the liner was seeing 900º+ temps. Can you see the liner? If so, what color is it?
 

valleyfire

Member
Sep 10, 2018
20
Massachusetts
An insulated liner is good and required by code for most installations. As for the wall temp, if you could hold your hand on the wall for 30 seconds then it was in a safe temp range and below 125º.

How is the T4 behaving with that tall liner? Do you have a damper in the flue or a thermometer? It could be that a lot of the heat is going up the liner due to too strong draft. It wouldn't surprise me if the liner was seeing 900º+ temps. Can you see the liner? If so, what color is it?
The wall was cool enough to touch for a while, but that was after the fire had died down some so I don't know how hot it got. No damper or flue thermometer; the stovepipe thermometer never exceeded 500 F. I can't see the liner.

The stove has done a great job heating the house - 1 log lasts 2 hours and keeps the house more than warm enough with outside temps below 0F. The house actually got uncomfortably warm with the 15 hour burn; usually in 0 or below temps, two three hour burns a day (morning and evening) would be enough.
 

begreen

Mooderator
Staff member
Nov 18, 2005
89,580
South Puget Sound, WA
Stovepipe or stovetop thermometer? Where is it placed?
 

valleyfire

Member
Sep 10, 2018
20
Massachusetts

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begreen

Mooderator
Staff member
Nov 18, 2005
89,580
South Puget Sound, WA
The thermometer is for single-wall stove pipe. This looks like Selkirk DSP double-wall stove pipe. It should have a probe thermometer. The surface thermometer can not provide an accurate reading of the flue gas temp. If the double-wall has been seeing 500º surface temps it means that the interior liner of the pipe has been very hot.
 
Last edited:

valleyfire

Member
Sep 10, 2018
20
Massachusetts
The thermometer is for single-wall stove pipe. This looks like Selkirk DSP double-wall stove pipe. It should have a probe thermometer. The surface thermometer can not provide an accurate reading of the flue gas temp. If the double-wall has been seeing 500º surface temps it means that the interior liner of the pipe has been very hot.
It is double wall stove pipe. Ok. What now? Pull the liner and have it checked for damage?
 

begreen

Mooderator
Staff member
Nov 18, 2005
89,580
South Puget Sound, WA
I would add a probe thermometer and I think you will find you need a key damper to reduce draft. The T4 is an easy breathing stove and 35 ft of liner is very tall. The probe thermometer will give you a much more realistic view of current operating temps. It will help illustrate the benefit of reducing draft by indicating a lower flue temp.

Less heat wasted up the flue = more heat in the house.
 
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valleyfire

Member
Sep 10, 2018
20
Massachusetts
I would add a probe thermometer and I think you will find you need a key damper to reduce draft. The T4 is an easy breathing stove and 35 ft of liner is very tall. The probe thermometer will give you a much more realistic view of current operating temps. It will help illustrate the benefit of reducing draft by indicating a lower flue temp.

Less heat wasted up the flue = more heat in the house.
Thanks so much!

Should I have the liner pulled and checked? Installing it in the first place was quite a job because there wasn't a lot of clearance, the chimney slants some in the attic, and our roof is steep (10/12 slope, maybe, hipped instead of gable).

Should I have the original installers determine whether a damper is appropriate?

Do I need to be concerned that the high temperatures might have damaged the stove itself?

Oh, and what do you mean by "easy breathing"?
 

begreen

Mooderator
Staff member
Nov 18, 2005
89,580
South Puget Sound, WA
Thanks so much!

Should I have the liner pulled and checked? Installing it in the first place was quite a job because there wasn't a lot of clearance, the chimney slants some in the attic, and our roof is steep (10/12 slope, maybe, hipped instead of gable).

Should I have the original installers determine whether a damper is appropriate?
If this were my house I would add one. I'm surprised the installer didn't recommend this. When you get the probe thermometer installed you will see what I mean. Burning one or two logs at a time would help keep the heat down. The liner should be inspected, but I am not sure about being pulled. bholler does inspections for a living. He would be better qualified to answer that question.
 

bholler

Chimney sweep
Staff member
Jan 14, 2014
25,497
central pa
Yes I would recommend inspecting the liner just to be sure it's ok. And yes a damper and probe thermometer is needed
 
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valleyfire

Member
Sep 10, 2018
20
Massachusetts
Yes I would recommend inspecting the liner just to be sure it's ok. And yes a damper and probe thermometer is needed
Thanks. Can the liner be inspected without removing it? Does the inspector lower a camera?

Should we have someone check the stove too? Who, and what would they look for?
 

begreen

Mooderator
Staff member
Nov 18, 2005
89,580
South Puget Sound, WA
Thanks. Can the liner be inspected without removing it? Does the inspector lower a camera?

Should we have someone check the stove too? Who, and what would they look for?
The stove is likely fine. Most of the heat has been going up the flue.