My not so great experience with FPX catalyst insert - Advice?

[Ashful]

Yep, 16% stacked outside in WI is easy to do, 12% inside isn't out of the question at all.

There is no place listed in Wisconsin that will get wood to 12% equilibrium moisture content in February, when the OP was posting. If you just happen to live in La Crosse, and if you catch it on the right day in mid-July, you can get to 12.2%, but that wood is back up into the 14% - 15% range by winter.

See page 8 in the following table:

http://www.woodweb.com/knowledge_base_images/zp/equilibrium_moisture_content.pdf

 

[Woody Stover]

There is no place listed in Wisconsin that will get wood to 12% equilibrium moisture content in February, when the OP was posting. If you just happen to live in La Crosse, and if you catch it on the right day in mid-July, you can get to 12.2%, but that wood is back up into the 14% - 15% range by winter.

Yeah, I thought he had the wood drying inside, but re-reading I see that he just has the wood inside for long enough to get it up to room temp for testing. Point is, his wood is dry.

 

[Ashful]

Point is, his wood is dry.

Agreed. Likely not his issue. I'm just picking nits.

 

[Woody Stover]

I'm just picking nits.

What else is there to do, as we wait for the season to kick in..?

 

[webby3650]

If it’s the meter that came with the unit, it can very easily be misread. 1 light lights up a range, so 12% could also be 26%. Just a thought.

 

[clydesdale]

If it’s the meter that came with the unit, it can very easily be misread. 1 light lights up a range, so 12% could also be 26%. Just a thought.

I am the original poster and I ended up getting a new catalyst under warranty. The installer did not have the catalyst fully seated and therefore it was forward in the firebox and was getting "licked" by the flames too much. It destroyed the two center cubes of the catalyst. I also learned that 1200 is max. With this new catalyst, I also plan to vacuum it out if it gets sluggish. They are easy to remove and vacuum out.

 

[Tegbert]

I am the original poster and I ended up getting a new catalyst under warranty. The installer did not have the catalyst fully seated and therefore it was forward in the firebox and was getting "licked" by the flames too much. It destroyed the two center cubes of the catalyst. I also learned that 1200 is max. With this new catalyst, I also plan to vacuum it out if it gets sluggish. They are easy to remove and vacuum out.

I am willing to bet the installer did install the combustor right and it slowly moved out. Happens all the time on my rockport.

Don’t forget to have spare gasket material for when you do decide to pull it out too.


Lopi Rockport
Blaze King Ashford 25

 

[clydesdale]

I am willing to bet the installer did install the combustor right and it slowly moved out. Happens all the time on my rockport.

Don’t forget to have spare gasket material for when you do decide to pull it out too.


Lopi Rockport
Blaze King Ashford 25

ok, good to know. I will definitely watch out for that. Can that insulation around the cat be bought seperately ? Is it necessary? Does it protect the cat at all or just more efficient?

 

[webby3650]

I am the original poster and I ended up getting a new catalyst under warranty. The installer did not have the catalyst fully seated and therefore it was forward in the firebox and was getting "licked" by the flames too much. It destroyed the two center cubes of the catalyst. I also learned that 1200 is max. With this new catalyst, I also plan to vacuum it out if it gets sluggish. They are easy to remove and vacuum out.

That sounds like wishful thinking.. the flames pour through that cat no matter where it’s sitting. Make sure you’ve got plenty of interim gasket around for each time you pull the cat.

 

[clydesdale]

Any recommendations on where to get that fabric insulation that is around the cat? What do you think is wishful thinking?

 

[Tegbert]

I buy mine here.


www.firecatcombustors.com/ACIG-2-p/sku_acig-2.htm

And yes it’s necessary.

The design on these stoves allows the flames to hit it and they decided that it was not necessary to have a flame shield. Webby will tell you more as he used to and probably still does deal with them.


Lopi Rockport
Blaze King Ashford 25

 

[clydesdale]

I buy mine here.


www.firecatcombustors.com/ACIG-2-p/sku_acig-2.htm

And yes it’s necessary.

The design on these stoves allows the flames to hit it and they decided that it was not necessary to have a flame shield. Webby will tell you more as he used to and probably still does deal with them.


Lopi Rockport
Blaze King Ashford 25

So, it is essentially a design flaw? Ok, then plan B is that I will be replacing the center two bricks of the cat with the outer two bricks of the old one as time goes on. It is the center bricks that take the pounding. Thanks for the gasket link. Why is it necessary? Looking to learn. Thanks.

 

[webby3650]

The gasket is necessary, otherwise exhaust gases bypass the cat. It’s not a deal killer, but much less efficient. My comment on wishful thinking was thinking the cause for the failed cat was because it was out of place. A flame shield has historically been necessary to prevent cat failure, for some reason Travis ind. decided it wasn’t necessary. Cat failure would be expected with this design and has been proving to be the case.
These cats are “canned” meaning they are factory sealed into a stainless shell. I’m not sure how you could possibly replace the center two cells?

 

[Tegbert]

I’d have to look at my two new ones but the old one had four cells in a steel shell and they all could be removed. Although after a while of being used they would be brittle so I wouldn’t try to do it.


Lopi Rockport
Blaze King Ashford 25

 

[webby3650]

They are individual cells, I just don’t see any way to remove them individually without compromising the entire catalyst.

 

[clydesdale]

I can definitely remove each of the 4 cells in my old cat. I hate to think that I need to buy a new one of these things every 2 years. I think the position of the cat sped up the demize. I was able to push it back into place quite a bit. One major issue with this stove is that my father could never own it. He just likes to burn wood and call it a day. He is not looking for something that is complicated. His Buckstove is pretty sweet and no pain in the arse cat.

 

[webby3650]

I can definitely remove each of the 4 cells in my old cat. I hate to think that I need to buy a new one of these things every 2 years. I think the position of the cat sped up the demize. I was able to push it back into place quite a bit. One major issue with this stove is that my father could never own it. He just likes to burn wood and call it a day. He is not looking for something that is complicated. His Buckstove is pretty sweet and no pain in the arse cat.

Your cat should carry a warranty. 2 years is ridiculous! A cell falling out of the can is one thing, putting in a new cell wrapped in interim gasket is another. If it’s possible I’d be glad to know!

 

[BKVP]

A couple of points to make as it relates to combustors... not specific wood heaters.

The threshold temperatures where the washcoat becomes compromised is 1600F. If you had an electron microscope and examined a new combustor, it would look much like an English muffin. This provides tremendous surface area, turbulence etc. When a washcoat is subjected to 1600F, it will flatten out and lose that surface area. Repeated exposure results in peeling of the washcoat away from the substrate, essentially no longer having any catalyst activity. To be 100% clear, this happens regardless of substrate material. Do not "believe" that metal substrates are "better" because the substrate itself can withstand higher temperatures. It's the washcoat that counts.

As for flame shields, they do much more than protect against flame impingement. Flame shields, when properly engineered, help to spread the heat load more evenly across the face of the combustor. Also, when properly engineered, they create turbulence, all positives when engineering catalytic models.

As for gasket versus no gasket. The ability of the interam to expand and seal does more that help with bypassed emissions. It can, it most cases, help hold a combustor in place. It's also illegal to operate a wood heater other than as tested for certification.

Lastly, metal substrates do expand and contract more than ceramic. Diesel foil cats are notorious for this and as a result the cat can "walk", even when gasketed because repeated expansion and contraction loosens up the gasket over time.

All materials used in wood stoves expand and contract (those exposed to high temperature).

You will find ceramic combustors with cracks (not chips) and this is normal. That is why combustors are "canned" as webby points out. If blocks have cracks (again normal) and you press the blocks out of the metal can, they can often fall apart.

Thank you for reading this as intended.

 

[clydesdale]

Hi all,
For starters, thanks for all of the help on this forum.

I called Travis Industries and spoke with a tech rep. He suggested using a small piece of masking tape to keep the interim gasket attached to the combuster. The masking tape would then melt disappear. I bought the gasket material from the company that was linked in a previous reply. Thanks again for that.

So, any idea how I should do this? I am thinking of have the masking tape at the bottom near an edge. I am going to put the old cat in first. The tech seems to think I can replace individual cells as well. He also discussed cleaning them in vinegar. But, my old cat is way past that. It is crumbling and I am going to use it for the first two months of the season. I'll pop the new one in when January hits so that I have peek performance during the ugly months.

 

[jetsam]

I think anyone who is discussing replacing individual cells in a crumbling ceramic cat has possibly never seen a ceramic cat before.

While I'll go ahead and admit that it's possible, no parts are available, and you would need to cut the metal can, grind off the broken parts around the missing cells, insert replacement cells (which you cannot buy), wrap it back up, band it, weld it nicely, and grind it flat. You would also probably get an avalanche of broken fragments and powder once you cut the band if the cat is crumbling. So possible: yes. Would anyone actually do it? No. If a masochist decided to do it, would it be cheaper than a new cat? No, and the finished product would still be half worn out. Are the needed parts available to the consumer? No.

I really doubt that even substrate manufacturers make single cells. Who would even want to buy that and assemble it for coating when you can buy blocks of cells in your size and shape?

Tape-wise, just tape the gasket on the cat in its normal position. Your two goals with the tape are 1) to hold the gasket so the seam stays nicely together and 2) to cover the leading edge of the gasket so it can't catch on the stove when you insert the cat.

Don't worry about the tape- the cat runs at 1200 degrees. The tape will be gone first fire, and as it's all on the outside of the cat, its smoke won't pass through the cat.

 

[clydesdale]

I just re-installed the cat with the new interim gasket. I can definitely remove the two outer cells and have them remain in good shape. I slid them mostly out and then back into their place. The two inner cells are terrible and crumbling. They cannot be removed. So, I will use this crappy cat to start the season. Eventually, I will attempt to take the two center cells out of the crappy cat and replace them with the two out cells in my new cat, when that cat becomes crappy. I don't see why you have to cut the band to slip the 4 cells in and out. I appear to be able to move them. I agree, it will never be a new cat. But, I think my idea of using a half worn cat to start the season is potentially workable. We'll see. For the record, I did not come up with the idea. The installer told me to call him if I need a new cat, that he keeps the old ones and can make one work. He did not specifically say that he was swapping cells, but I got the impression that is what he might be referring to.

 

[clydesdale]

By the way, the plate that is right above the re-burn tubes is a touch warped and I noticed the gasket mat that lines it is a bit tired and worn. Do I purchase this mat from the same company as the interim gasket and then cut to fit, or is this an FPX part? Thanks.