Anyone ever see this from a stainless steel flu liner?

Is it corrosion? Corn is very corrosive. I am not saying that's what you burned, but the burning of pellets and the byproducts that comes from them are very corrosive over time. Especially if the sit in the flue for extended periods of time over the summer. Do you do a full "Spring Cleaning" at the end of the season? I cannot imagine that it came with those holes it it, and you never notice. Hope you figure it out.

Hello

Is it Metal eating Moths???

G.Head:
It does look like corrosion - and could be although stainless is not supposed to corrode. That said, there are different grades of stainless so I could imagine a very low grade stainless may have this issue.

If it is corrosion it is likely from water getting down your chimney / flue. The water mixes with ashes in the pipe to form a caustic compound which can then attack the iron in the stainless steel. Is the top of the vent covered with something to stop the rain from coming down?

I not you mention the bottom 10 feet is more attacked than the top of the flue. This aligns with the theory of water (rain) coming down the stack. Any water that contact the side of the flue higher up would form water droplets and these would tend to run towards the bottom of the pipe.

My advice: Replace the whole thing ... I'm guessing the quality of that flue pipe is marginal.

Take care

RonB

goathead said:

Yeah, kind of looks like corrosion or burn through. Just kind of worried me that I wouldn't have caught it if I wasn't moving the stoves around.

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Well. I'm glad your getting the new stove. Also glad that everyone is o.k. Holes in any exhaust, directly correlates to CO leaking inside the building (House). Because its a liner and I dont have an application that needs one, means I know little about them. But I would have to ask you, Are you going to buy another?

goathead said:

......new one I bought and installed in my other chimney myself has a lifetime warranty which includes corrosion protection so I'm wondering what the other one was......

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Are you sure it was stainless?? Try a magnet on it. Sticks = steel No stick = stainless

imacman said:

Are you sure it was stainless?? Try a magnet on it. Sticks = steel No stick = stainless

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Not true Imac. I used to work in the water treatment industry. I am not sure how many different grades of stainless there are, but it is a lot and the lower in grade you go the more iron is added to the mix and they still call it stainless.
We ran into this problem time after time especially with chemical addition pumps. It is amazing how fast acid will corrode a pump that is not stainless. The only reason I found out about was cause I use to take all the scrap to the salvage yard and the man did the same thing, he held a magnet up to it and it stuck. It was low grade stainless and he would not take it.

There is a Dealer in my area, that does not keep the termination cap's on his stoves during the winter months. (They run a 50/50 mix - corn/pellets) They were replacing them every 2-3 years because they were being eaten alive by corrosion. Only put them on in the summer for pests. I know its not the same as "Just Pellets", but figured I would share.
Even if it is stainless, its not indestructable. Everything meets its maker sooner or later. Nothing is made to last forever, Unfortunately........ :-S

Ed S said:

.....not sure how many different grades of stainless there are, but it is a lot and the lower in grade you go the more iron is added to the mix and they still call it stainless......

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I know that. My point ( w/o actually saying it) was that if a magnet sticks to it, then it's obviously either steel or low grade stainless......in either case, corrosive exhaust will eat away either one eventually.

OK, just sharing.
I did not believe how many different grades of stainless are made until we actually started talking about it one day cause we need over 1000 ft for a pipe run.

Ed S said:

imacman said:

Are you sure it was stainless?? Try a magnet on it. Sticks = steel No stick = stainless

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Not true Imac. I used to work in the water treatment industry. I am not sure how many different grades of stainless there are, but it is a lot and the lower in grade you go the more iron is added to the mix and they still call it stainless.

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Actually its carbon content that seperates the different Stainless Steel grades. More carbon=Lower grade. 316 grade SS isn't magnetic and has very little carbon content. 304 is what most liners are made of and they do contain carbon and are magnetic. 304 should only be used for wood fuel because the corossives in the multifuels attack the carbon. Most multifuel rated pipe/liners and made of 316SS. FYI only!

I've got 15 ft of Simpson Duravent SS Flex Liner (installed in 2005)
going up my chimney and a magnet does not stick to it. Just an FYI.

Enjoy the debate. You guys crack me up.

Didn't someone find corn in newp? I thought they sold a mix ... maybe thats what you were burning

iceman said:

Didn't someone find corn in newp? I thought they sold a mix ... maybe thats what you were burning

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Freedom fuel had the corn.

To the OP that doesn't look like corrosion to me, that normally shows up as pin pricks. That looks like something was driven into the liner somehow.

Xena said:

....You guys crack me up.

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We live to amuse. :coolsmile:

goathead said:

So I did the pellet stove swap today and after I trimmed my existing liner for the new stove I was looking at the piece and I noticed holes in it. At first I thought maybe I nicked it when I was cutting but upon closer look that wasn't the case. So then I looked at the rest of the liner and noticed the same type of holes for a few more feet. I wound up pulling out the whole liner and these holes ran for the 10 or so feet of the liner. Surprised me to say the least, anyone ever seen something like this before? The liner is 7 years old and I clean it every year.

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See that in coal and corn liners , not in pellet liners.

What was burned in the flue you ran the liner up before you got your stove?

G.Head:
You mentioned you had this liner installed by a dealer 7 years back -- and you've only ever burned hadr wood pellets --- could that dealer have taken a short cut and installed a used liner from another application? Coal or corn, maybe?

Just a thought. I'm sure it happens.

RonB

Very strange indeed. My flex liner is 6 yrs old.
At the end of the season when I clean it out
I'll shine a flashlight up the liner to see if I notice any
holes. I don't see any in the lower portion
that is visible in the fireplace area.