cat falling apart in my indoor wood burner... Suggestions for a new one?

[nstueve]

hey guys,
I'm usually over in the chainsaws section but needed some advice from other wood burner experts, or at least more knowledgable than me...

We have a new englander indoor wood burner and it origionally had a strait thru honeycomb cat (2inch thick I think??). It started to crumble and so we replaced it. It looked like this...
http://www.motherearthnews.com/uplo...ssues/1981-01-01/067 wood stove pollution.jpg

It was replaced by a 1-1.5in thick spider webby snarly cumbustor that we just dropped in so we could take out an clean more often.

I guess the overall problem is that both cats have choaked the stove to the point where we have to run the air damper all the way open to keep the stove at 250*F stack temp. I would assume a higher flowing cat would allow a better air charge to be taken in and thus make the air damper a better temperature/air flow control.

ANyhow does anyone have any ideas on what I should buy? Saw some round ceramic cats, or stainless maybe???

thanks in advance!
Nathan

 

[Patrick62]

I did a little poking around the web...

I have never used a cat stove. From what I read they operate a little different than what I would expect.
I did find a small thread on the newer stoves with the secondary combustion actually working better.

I know about what I would do with this stove, but will not mention due to a matter of legality :angrysoapbox:

 

[EXCALIBER]

Why are you concerned about the stack temp? Heat should be coming from the stove, not the stack? The whole idea in a cat is to reduce the temp that it takes to burn the gases off of the wood, thus reducing stack temp, and raising efficiency while giving you a larger adjustment for the amount of heat your stove gives off.

 

[nstueve]

I have never used a cat stove. From what I read they operate a little different than what I would expect.
I did find a small thread on the newer stoves with the secondary combustion actually working better.

I know about what I would do with this stove, but will not mention due to a matter of legality :angrysoapbox:

I'd get rid of the cat all together b/c where I live no one cares about the extra particulate coming out the stack. The reason I keep is is b/c the cat is mounted on top of the air2air exchanger. Thus the cat heats up the air exchanger and increases heat output by about 50%. If the stove would heat just as well without it I'd get rid of it but they unfortunatly designed this thing to be a PIMA...

Why are you concerned about the stack temp? Heat should be coming from the stove, not the stack? The whole idea in a cat is to reduce the temp that it takes to burn the gases off of the wood, thus reducing stack temp, and raising efficiency while giving you a larger adjustment for the amount of heat your stove gives off.

When you have a cat stove, you're supposed to bring the burner temp up before closing your bypass to divert smoke through the cat. Otherwise you get premature clogging and other problems.

off condor website...
"Excessively high temperatures can shorten the catalyst’s life and cause thermal cracking. The catalytic reaction usually begins at temperatures over 500 degrees F, with best operating temperatures between 600º and 1500º. Avoid higher temperatures to prevent damage to the combustor."

I started looking around and don't know what to think about what to get... $100-$200 is a rip for a little 6inch cat element but the stove needs it. If this were my house and my stove I would have put a wood boiler/gasifier by now.

 

[EXCALIBER]

Yes I know, I have a cat stove and on the third year of use. It's the only source of heat besides chili night. What I am saying is a cat stove should have very low stack heat as more of the smoke is being burned in the cat, leaving less wasted energy to go up the stack. The only reason I would worry about my stack temp is if the stove was not drafting correctly. If you are getting a good draft the stack temp is irrelevant. If the cat is still working, and the stove is putting out good heat, forget the stack temp. You should be measuring the stove temp of when to close the bypass allowing the gas to go through the cat, not the stack temp. Guess I am confused.

 

[Patrick62]

charming

Not even your stove. Nice situation. You gotta maintain a system that isn't yours.
200 bucks is a rip, but so would be heating with another source.

I would stare at the stove, and see what would have to be created to mimic the newer stoves that have air tubes in the exhaust path that creates a re-burn system. Best solution would be to change it out to a different stove.

For now.... buy a new cat?

 

[elmoleaf]

Those spider-webby cats (ClearSkies product) clog very easily.
I went back to the straight-thru grid style which required only a brush off once or twice a year to remove fly ash. FireCat combustors by Applied Ceramics has quite a variety of sizes.

 

[nstueve]

Those spider-webby cats (ClearSkies product) clog very easily.
I went back to the straight-thru grid style which required only a brush off once or twice a year to remove fly ash. FireCat combustors by Applied Ceramics has quite a variety of sizes.

any comment on Steel vs Ceramic???

 

[elmoleaf]

any comment on Steel vs Ceramic???

I've never used steel. From what I remember, they are more expensive than ceramic. They are supposed to be more durable (no cracking) but I recall reading about problems with them warping/distorting that made me wary. In my Vermont Castings stove, the cat fits tightly inside an expensive refractory box that can be easily destroyed by an overly warped cat, so I've stuck with the ceramic straight-thru grid type.
I've never had any problems with the cat crumbling.

 

[nstueve]

I've never used steel. From what I remember, they are more expensive than ceramic. They are supposed to be more durable (no cracking) but I recall reading about problems with them warping/distorting that made me wary. In my Vermont Castings stove, the cat fits tightly inside an expensive refractory box that can be easily destroyed by an overly warped cat, so I've stuck with the ceramic straight-thru grid type.
I've never had any problems with the cat crumbling.

The ceramics will crack and crumble over time... I think we've had this wood burner for 20+ years now. When I say "we" I mean my parents, who are renting their house to me and my wife... It's the house I grew up in and so I feel the need to take care of it for them... Anyhow... Our origional ceramic cat started to deteriorate after 5-7 years and I think we streched it to 10 years. Then we replaced it with this webby designed cat that is now falling apart. To be honest I don't think my dad hardly ran the stove for 3-5 years while I was in college... So we are at the end of a 5-7 year life on this cat and just want to know what to do next.... I would have thought there would be many more guys on here that had the same problems and questions...

Either way I think it's back to the ceramic or maybe spring for the metal type since they are only $75 more... If I get 3 extra years out of it or extra BTU value like they claim I'm sure the cat will be cost neutral in the end...