Bending/warped air tubes

[NorthWind100]

Hi Folks,
Hoping someone can tell me if my idea of why the air tubes are falling is correct. We've been using our wood stove for about 4 years, is great. I absolutely love it. It has saved us thousands in oil bills and heats the house so nicely.

Twice now, an air tube (maybe called secondary air tube?) bent, and fell down. The tubes I'm talking about are in the ceiling of the stove. The bricks (light weight things) sit on top of these tubes. The tubes have holes in them. So I think I'm calling them the right thing... air tubes.

Anyway, it seems when the fire is too hot, when it burns full out, for too long, these tubes warp or bend. The cotter pin lets go and the tube falls down on one side. My husband has straightened the bend once it cooled and placed it back in the stove.

I only burn the stove wide open, once a day, in the morning for about 20 mins, to 'clean it out'. Apparently this clears out soot etc., and it's true, it does clean off any black on the glass door that sometimes builds up over night. Once in a while someone forgets to shut the stove down (close the draft). It happened today. I noticed the house felt cold, went to check the fire and saw that there was a roaring fire going and the air tube had fallen down. I also noticed that the fan wasn't on. Which it should have been, with the massive amount of heat the stove was producing. I played around with the fan a bit, checked that the electrical outlet was working etc. The fan must have just died. So, to sum it up, the fire was burning high, the fan died, the stove got really hot, the air tube warped and fell down. Or at least this is how I figure it all to have happened.

My husband on the other hand, tells me the tubes are only there to hold up the bricks and serve no other purpose. And that they get knocked down when "stuffing' wood into the box. Obviously, this isn't true. But has it happened to anyone else, that the tubes warp/bend and fall down? The tubes are in good condition otherwise, no holes, corrosion etc.

 

[DAKSY]

Wanna tell us what stove you're burning? That will narrow down the field to others who are burning the same unit.

 

[begreen]

My husband on the other hand, tells me the tubes are only there to hold up the bricks and serve no other purpose. And that they get knocked down when "stuffing' wood into the box. Obviously, this isn't true. But has it happened to anyone else, that the tubes warp/bend and fall down? The tubes are in good condition otherwise, no holes, corrosion etc.

You are much wiser than he. What is the stove make and model?

 

[Woody Stover]

Yep, air tubes. With well-seasoned wood, you should see flames coming off them and burning the smoke once you have some wood burning after reloading. Once that happens you should be able to cut the air down pretty far to extend the burn time while still providing heat. Running it wide open flushes a lot of heat out the chimney, and can possibly overfire and damage the stove.

 

[NorthWind100]

It's a Timberwolf EPI22. This is the product website link https://timberwolffireplaces.com/products/wood-burning-inserts/epi22/
I am in Canada. We start this stove up in October, and it is going constantly until April. We light the fire maybe 5 times over this period, as there is never a need to re-light, as it is burning constantly.
I've attached pictures of the air tubes.

Wanna tell us what stove you're burning? That will narrow down the field to others who are burning the same unit.

 

[NorthWind100]

Yep, air tubes. With well-seasoned wood, you should see flames coming off them and burning the smoke once you have some wood burning after reloading. Once that happens you should be able to cut the air down pretty far to extend the burn time while still providing heat. Running it wide open flushes a lot of heat out the chimney, and can possibly overfire and damage the stove.

Thanks. Yes, we do 'shut it down' once the burn is established. Then the fire burns well, for a very long period of time. It can last for more than 8 hours. But once in a while, we forget to shut it down. And that is what seemed to cause the problem. The stove got too hot, and the air tubs bent. Is this possible?

 

[DAKSY]

Looks like you'll hafta call to see if replacement tubes are still available...
(broken link removed)

 

[djkeev]

Metal is refined out of iron ore (rock) by using high heat and melting it.

Once you have the refined iron, you shape it by heating it.
Very high heat gives you a liquid you can pour into forms,
"Lower" heat simply turns the metal red hot and you can manipulate into almost any shape desired.

Red hot metal, while still a solid, is soft and can be bent almost as easily as bending a pipe cleaner.

Your wood fire on a hot burn is capable of turning your metal tubes red hot. Gravity then causes them to sag and they simply fall out of their holders.

Different grades of steel handle heat differently. If you can, it may be wise to source a few new tubes to keep on hand.

Watch your fire, too much heat will damage more than just these tubes.

Dave

 

[NorthWind100]

Thanks everyone. Appreciate the info. We will straighten out the air tube and put it back in. So just to be clear... it is the high heat of the stove doing this? Not the tubes being knocked out of place?

 

[Mark8]

Does anyone know what grade of stainless steel tube the manufacturers use for their secondary burn tubes?

Does anyone know if there is any special process being used to manufacture them, like heat treated?

304 or 306 stainless tube cost about $60 and I can drill my own holes, the stove manufacturers want $450 for their tubes on my model of stove.

 

[Mark8]

Thanks everyone. Appreciate the info. We will straighten out the air tube and put it back in. So just to be clear... it is the high heat of the stove doing this? Not the tubes being knocked out of place?

Yes it's the high heat that's making them sag.

 

[Easy Livin’ 3000]

Hi Folks,
Hoping someone can tell me if my idea of why the air tubes are falling is correct. We've been using our wood stove for about 4 years, is great. I absolutely love it. It has saved us thousands in oil bills and heats the house so nicely.

Twice now, an air tube (maybe called secondary air tube?) bent, and fell down. The tubes I'm talking about are in the ceiling of the stove. The bricks (light weight things) sit on top of these tubes. The tubes have holes in them. So I think I'm calling them the right thing... air tubes.

Anyway, it seems when the fire is too hot, when it burns full out, for too long, these tubes warp or bend. The cotter pin lets go and the tube falls down on one side. My husband has straightened the bend once it cooled and placed it back in the stove.

I only burn the stove wide open, once a day, in the morning for about 20 mins, to 'clean it out'. Apparently this clears out soot etc., and it's true, it does clean off any black on the glass door that sometimes builds up over night. Once in a while someone forgets to shut the stove down (close the draft). It happened today. I noticed the house felt cold, went to check the fire and saw that there was a roaring fire going and the air tube had fallen down. I also noticed that the fan wasn't on. Which it should have been, with the massive amount of heat the stove was producing. I played around with the fan a bit, checked that the electrical outlet was working etc. The fan must have just died. So, to sum it up, the fire was burning high, the fan died, the stove got really hot, the air tube warped and fell down. Or at least this is how I figure it all to have happened.

My husband on the other hand, tells me the tubes are only there to hold up the bricks and serve no other purpose. And that they get knocked down when "stuffing' wood into the box. Obviously, this isn't true. But has it happened to anyone else, that the tubes warp/bend and fall down? The tubes are in good condition otherwise, no holes, corrosion etc.

I am dumbfounded that no one here is telling you that you guys are badly overfiring your stove! Leaving the air open (forgetting) is getting your stove way too hot. I mean, does the fact that you are getting steel close to it's melting point not make this obvious?

You are destroying the stove burning it like this (not just the tubes) and risking burning your house down.

Your husband couldn't be more wrong. Holding the baffle up is but one of the tubes' functions. The other function is to burn the combustable gasses that come out of the wood to make the stove more efficient and cleaner burning.

Please read the manual to the stove.

 

[djkeev]

Does anyone know what grade of stainless steel tube the manufacturers use for their secondary burn tubes?

Does anyone know if there is any special process being used to manufacture them, like heat treated?

304 or 306 stainless tube cost about $60 and I can drill my own holes, the stove manufacturers want $450 for their tubes.

Ideally 316....... 330 is better but not sure of ready availability in tube format

Go for a thick wall also.

Dave

 

[Mark8]

Ideally 316....... 330 is better but not sure of ready availability in tube fo

Dave

306 was a typo, I ment 316. Is it safe to say the manufacture is just using stock tubing and drilling holes? I wouldn't think the stove manufacturers are making their own stainless tubing, I'd guess it's outsourced from a steel manufacture. Thanks Dave


STAINLESS STEEL 330 TUBE APPLICATIONS:

Alloy 330 is extensively used in high temperature environments where resistance to the combined effects of thermal cycling and carburization is necessary. Applications include:

• Chemical and Petrochemical Processing: cracked ammonia components, petrochemical furnace parts, heat exchangers, flares, etc
• Thermal Processing: heat-treat furnace containers & compartments, high temperature fans, salt pots, etc
• Ore Processing: perlite system and equipment
• Power Generation: boiler fixtures, gas turbine components, etc

http://www.stainlesssteelplatesshee...sfasterners.com/stainless-steel-330-tube.html

http://www.onlinemetals.com/merchant.cfm?id=18&step=2&top_cat=1

 

[Eureka]

One of the most over fired stoves I’ve seen in a while. I’ve owned 3 EPA stoves and have gotten all of them way hotter than my comfort level at one time or another and I’ve never seen anything warp other than a thin air wash deflector. Air tubes always glow, those have been severely abused to warp like that. It’s time to revise your burning practices as that is extremely dangerous to run like that.

 

[begreen]

Those tubes are shot. They should be replaced. The stove is being overfired. It should be inspected by a pro to make sure nothing else is damaged. If it is ok, get new tubes and get a good stove top thermometer so that you can track how hot the stove is getting and know when to tell hubby to turn it down.

Has hubby read the stove manual?

 

[Highbeam]

Do you think heating has ruined the alloy? I know that you can greatly change the material properties of steel alloys by heating, cooling, quenching, etc. If the tubes were super hot it is possible that even after bending them straight that they are now just wet noodles and need to be replaced.

450$ Ouch. My tube stove tubes are about 100$ apiece too but at least they don’t clog. Right @begreen ?

Be sure to consider a larger 600$ replacement stove. One with no history of melting tubes, such as the nc30 instead of repairing your Timberwolf.

 

[Highbeam]

Oh and there is a lot to those holes in the tubes. On my nc30 the hole size is different on each tube. The angle below horizontal is different too.

 

[Easy Livin’ 3000]

Oh and there is a lot to those holes in the tubes. On my nc30 the hole size is different on each tube. The angle below horizontal is different too.

Yes! Highly engineered, they are! Perhaps you could approximate the baffle holding capacity with homebrew replacement tubes. But, please don't. Lots of gasses are burning at top of the stove because of the careful placement of the holes in the tubes. Keep all that heat energy inside the house.

 

[begreen]

Be sure to consider a larger 600$ replacement stove. One with no history of melting tubes, such as the nc30 instead of repairing your Timberwolf.

The EPI22 is a 1.9 cu ft insert. The Englander 13NCi would be close. The mid-sized Drolet and Century inserts would also be about the same size. However, it the need is for more heat then increasing the size of the stove would help, if there is room in the fireplace and budget.

 

[Woody Stover]

The stove is being overfired..get a good stove top thermometer so that you can track how hot the stove is getting

And use the timer on your phone in case you get distracted while ramping up a new load, so you can cut the air in time and keep stove temps within bounds.

 

[blacktail]

So just to be clear... it is the high heat of the stove doing this? Not the tubes being knocked out of place?

You'd have to try pretty hard to knock one out of place and bend it like that.

 

[Mark8]

You'd have to try pretty hard to knock one out of place and bend it like that.

Are you implying the bend didn't happen from an 18" fall to funny.

Sorry couldn't resist.
The stove looks like it's been through a nuclear Firestone/meltdown, and were wondering if bumping the tubes caused this. Friken hilarious!

 

[firefighterjake]

It's a Timberwolf EPI22. This is the product website link https://timberwolffireplaces.com/products/wood-burning-inserts/epi22/
I am in Canada. We start this stove up in October, and it is going constantly until April. We light the fire maybe 5 times over this period, as there is never a need to re-light, as it is burning constantly.
I've attached pictures of the air tubes.


View attachment 222758 View attachment 222759 View attachment 222760

Wow . . . just . . . wow.

 

[BrotherBart]

Help her out folks. What this thing is about.