Liner pic, I am stumped and discouraged

[Jags]

. I either had to burn wet wood or cut the air off early so the secondary burn never got going, once the secondaries lit it was going to cruise at 650-700* no matter what I did.

Yea, all the tubes and the entire baffel plate are usually glowing bright orange on mine. The radiant heat through the door glass is enough to burn you if you are within 4-5' of it for any length of time, did that once and I had what looked and felt like a sunburn.

I had to run the blower on high to keep it at or below 700. The blower must have some sort of thermal overload switch because occasionally the fire would get get roaring and then the blower would just turn off, if I didn't get a fan blowing on high into the blower intake area quickly (to both keep the stove cool and to cool the blower back down) it would go from 700 to much higher very quickly. Also running it at 700 is with the air closed down.

Wait - one does not equal the other. I am getting mixed signals here. Cruising at 650-700 is a far cry from needing to force cooling air into the blower intake to keep it from screaming past 700F.

 

[brian89gp]

Cruising at 700 with the blower running on high. Mine is an insert so the blower is always on, "cruising" = "cruising wither the blower on" to me, I apologize for the confusion.

Sometimes the blower overheats and shuts off (once a month or so, usually right after emptying the ash, blower is under the firebox so that makes sense) and if that happens I have to force air into the blower intake to cool the blower down so it will turn back on, otherwise the stove face temp will start climbing above 700 rather quickly if the blower happened to have overheated during the beginning of the secondary burn cycle.

 

[Dave A.]

Sounds to me like the fiberglass melted and effected the insulation wrap on the rock wool as you say. But still that doesn't explain the failure of the liner, afik. The fiberglass insulation should not be against a flue.

You are sure the liner has failed. Have you run a brush in there at all, to clean out and see better what's going on?

 

[Jags]

Thanks for the clarification. I am still interested in what you find out about the liner. It takes over 2500F to melt 316 stainless (about the temp at which a blow torch will run) whereas aluminum is a bit over 1200F.

 

[brian89gp]

You are sure the liner has failed. Have you run a brush in there at all, to clean out and see better what's going on?​

Yea. It is a smooth bore liner, those ridges you see are of the edges of the metal peeling up. Also up near the top of the picture there is a gap you can see insulation where the liner seperated from itself. The thing has so many sharp metal edges, gaps in the liner, and is so deformed I couldn't get a brush in there even if I tried.

 

[oldspark]

"Yea. It is a smooth bore liner, those ridges you see are of the edges of the metal peeling up"
That's good I thought you had put in drain tile

 

[brian89gp]

Manufacturer says it is from overtemp, liner is rated for 2100* for short periods. Chimney fires melt the liner at the top, an overtemp the bottom generally. They said the white ash I have on top of the baffle plate area also suggests overtemp as those are from very hot fires. The deformation is from overheating.

So.... Do I get some sort of reward for building a gassifier class fire in a secondary burn stove?

Damn happy I didn't burn my house down.

 

[Jags]

So.... Do I get some sort of reward for building a gassifier class fire in a secondary burn stove?

You get the "Damn lucky to be alive" award.

If that is their answer and you are satisfied with it then we go back to "you have some operational procedures that need some serious review".

But none of that matters till you get that liner replaced.

 

[brian89gp]

If that is their answer and you are satisfied with it then we go back to "you have some operational procedures that need some serious review". But none of that matters till you get that liner replaced.​

Don't worry, not going to build a fire with the liner like that. I'm too busy this year to mess with it so it will likely be out of commission until the winter of 2014/2015.

A little digression into operating procedures, cause if I just replace the liner I will likely be taking a similar pic next spring if I am still alive. So, if I have the air shut down and the blower on high in order to keep it below 700*, that suggests that my super tall flue, strong draft, and an EPA stove that can't fully be shut down is just a bad combination. The only way I can think of to avoid the constant 700* burns is either to only ever fill the firebox half full or shut the air down early enough so that it never enters secondary burn, both of which greatly diminish the reason for the stove in the first place. It only ever heated about half of the house well anyway, so there is room for improvement there too.

I am thinking that I need to fix the strong draft somehow, perhaps with a 5" or 5.5" flue instead of a 6" one, but then I am still stuck with a undersized stove for the house. I could switch to a different method of wood heat such as a forced air wood furnace or gassifier boiler. Wood furnace would be in the basement so the flue would be even longer, and for the gassifier I don't have the room for storage tanks. Or call it a lesson learned and go back to natural gas.

 

[mellow]

I would have someone that is a NCSG or CSIA certified come and look at that liner and give you their opinion of your operations and setup onsite.

 

[DanCorcoran]

From what I've read on this site, you reduce your draft by putting in an oversized flue, not a smaller one, or by installing a damper. Those in the know, please feel free to educate me!

 

[brian89gp]

650 F ain't hurting that stove.

There is an air space between the top of the firebox and the top of the stove that the blower blows air through. Looks like I might have had an overfire that I didn't notice.

 

[Locust Post]

I would not just accept the explaination that you had a chimney fire or over heat here. If you swept like you said at mid season and had little in the flue this just doesn't add up. I understand a liner is made for short periods of 2100 but even 1200 to say 1500 is a lot of heat just from a run away stove. I would think you would have had an excessive build up (creosote/fuel source) to burn that hot in the flue. Which to me does not sound right especially if you were burning on the hot side.

 

[brian89gp]

Bleached fiberglass insulation
Melted liner insulation foil backing
Very stiff liner insulation, stove is about 1" further down out of frame

 

[brian89gp]

Baffle plate insulation. It sits directly below the flue opening so you would think there would be some evidence (black stuff) of a flue fire.
Weird rust on baffle plate

 

[brian89gp]

The liner throws sparks, it is 316 stainless.

I have a certified chimney sweep coming out on the 10th to take a look.

 

[begreen]

It sounds like the flames are getting sucked right up the chimney as you described. Consider switching to a 5" liner or at least put a 12" rigid stub with a key damper in the flue collar and attach the liner to that. And burn much thicker splits if possible.

 

[brian89gp]

Lets see if I understand the concept with the smaller liner. The draft would naturally start easier and would be ramp up quicker at lower flow rates, but the maximum possible flow rate would be less. Since hypothetically my constant over-burn scenario is at maximum draft on a 6", going to a 5" would lower the maximum draft and thus reduce the over-burn problem. I am assuming that the temperature differential, which would be a main factor in draft volume, does not increase with a smaller liner.

But the typical slammer install proves the opposite of this with poor drafting due to a larger flowing flue. Or is that because there is not enough heat/gasses to induce a maximum flow rate condition?

 

[BrotherBart]

Yeah I have two 5.5" liners. One 33' and one 21' foot and have great draft with the 21' and insane draft with the 33'. I have always thought that velocity is higher with the smaller pipe. I have to use a key damper in the connector pipe to the 33' to slow that puppy down and have times that I wish I had a way to put one in the 21' liner.

I think you are right. 8" would relieve some of the overdrafting. I would also install smooth wall liner with the open side of the strip in the inner layer up, not down so heat doesn't blast under the strip. I took out my double wall after one season and replaced it with single wall because of so many spots where the dang thing opened up space in the inner strip when it was un-coiled.

But with the top plate warped and that liner trashed there has to be some massive burning going on in that stove. I originally had my old pre-EPA insert hooked to the double wall liner and had two runaways with the thing where the flue collar got to 1,400 degrees and 1,325 stove top and it didn't trash the liner.

 

[brian89gp]

Warped top plate that has like a 1" air gap to the top plate of the firebox.

I found the following text in a US Stove wood furnace manual in reference of when to use a barometric damper. It seems to back up the concept of going to a smaller liner.

In the unlikely event that your furnace “overfires” then your installation is subject to excessive draft created by either a chimney too tall or too great in diameter in conjunction with its height, or some other factor of an indeterminate cause.

In all honesty though, I will still be trying to heat a 3500 sq/ft house with solid masonry walls (eg, they get cold in the winter) with a 2.4 cu/ft firebox stove. I am giving serious pause to the idea of fixing this setup and instead cutting my losses and putting in a properly sized wood furnace in the basement. As it was, the room with the stove ran a constant 90-95* just to keep the other parts of the house in the 60's.

 

[oldspark]

Yep get the furnace.

 

[BrotherBart]

Yeah that much space is wood furnace territory. I still wish I had put one in here in the eighties like I started to. And I am heating a thousand sq. ft. less than you are if I don't heat the basement. When I heat the basement too I run two stoves.

Put a nice gassifier furnace in the place.

 

[webby3650]

I either had to burn wet wood or cut the air off early so the secondary burn never got going, once the secondaries lit it was going to cruise at 650-700* no matter what I did.

Wet wood is the best way to ensure that you have a flue fire. 650-700 stove top temps will NOT cause this kind of damage to a SS liner, or cause the top of the stove to warp. Where are you taking these temps? These temps are normal for a steel tube style stove.

The outside of an insulated liner should barely be hot while in operation. Yours was hot enough to melt the aluminum on the outside of the insulation and deform the fiberglass insulation, right? There is no way a "normal" fire could do this. An old smoke dragon with no damper or baffle wouldn't even have an issue like this unless there was a Flue Fire. The temps experienced in a flue fire are the only time that you are gonna see damage like this. Sorry, but a flue fire is to blame.

 

[brian89gp]

Where are you taking these temps?

Face of the stove, right next to the top right corner of the door.

The outside of an insulated liner should barely be hot while in operation. Yours was hot enough to melt the aluminum on the outside of the insulation and deform the fiberglass insulation, right? There is no way a "normal" fire could do this.

Correct. I also warped the top plate of the stove by 1/4" over a 12" span which takes quite a big of heat to do.

I don't understand how I could have had a massive flue fire pretty much in the first few inches of the liner and not have any other signs of it, especially burning dry wood and with zero creosote at the mid-season cleaning.

 

[webby3650]

I don't understand how I could have had a massive flue fire pretty much in the first few inches of the liner and not have any other signs of it, especially burning dry wood and with zero creosote at the mid-season cleaning.

In the pic, it looks like several feet of damage.

Zero-creosote is good evidence of a flue fire, all the evidence was consumed by the fire.