NGC-wood stove catalyst

[Aaron D.]

Since there are many experienced wood burners here I thought I'd run this question/impression by the crew.

Condensed background-Elmira fireplace insert that came with the house. Previous owners used it for decorative purpose-and I had never had an insert so it took me a month or 2 to realize I should have a blower (made one) and that it would accept combustors.

It worked ok. The blower allowed for some heat, didn't know if the catalysts did anything. I could never get the stove to accept full closure of the bypass, but I thought it was just the way it was.

Recently had a liner installed. Suddenly the thing works REALLY well and can heat the whole house-bypass closes  within 20 minutes of light.

So the point-I decided to inspect the catalysts, one was a pile of rubble and the other was plugged up, and fell apart in my hand.

My impression after reading what I could is that catalysts are really designed to operate when the stove is closed down a bit. I can find new ones easy enough but I also (now) understand they last about 2 years and can be fussy about the wood burnt.

I'm thinking it isn't really worth the expense. Since I tend to run the fire hot I get near to no smoke, or soot, and since it's small I'm not in the effective range for them to work efficiently.

Thoughts/essays?

[Lannis]

Since there are many experienced wood burners here I thought I'd run this question/impression by the crew.

Condensed background-Elmira fireplace insert that came with the house. Previous owners used it for decorative purpose-and I had never had an insert so it took me a month or 2 to realize I should have a blower (made one) and that it would accept combustors.

It worked ok. The blower allowed for some heat, didn't know if the catalysts did anything. I could never get the stove to accept full closure of the bypass, but I thought it was just the way it was.

Recently had a liner installed. Suddenly the thing works REALLY well and can heat the whole house-bypass closes  within 20 minutes of light.

So the point-I decided to inspect the catalysts, one was a pile of rubble and the other was plugged up, and fell apart in my hand.

My impression after reading what I could is that catalysts are really designed to operate when the stove is closed down a bit. I can find new ones easy enough but I also (now) understand they last about 2 years and can be fussy about the wood burnt.

I'm thinking it isn't really worth the expense. Since I tend to run the fire hot I get near to no smoke, or soot, and since it's small I'm not in the effective range for them to work efficiently.

Thoughts/essays?

The catalytic converter in my Englander stove lasted the 25 years I had it, and may be still working now.    You used a handle to slide it out of the heat/exhaust stream while you were starting the fire, then slid it into place once the fire was going good.   

The first time I cleaned it, years ago, I didn't realize that it was ceramic and I chipped it a bit getting the soot off.   After that, I was more gentle with it and didn't knock any more bits off.

It looked like a "coarse" version of a car converter element.   Whereas the ceramic converter in a car has holes about .008" in diameter with similar sized ligaments, the holes in this were made like a hexagonal honeycomb, with holes about 1/8" across.

When I cleaned it, I just vacuumed the accumulated soot and creosote chips that had fallen from the pipe over the years - the holes themselves never clogged up internally.   I never used pine, but used about any sort of hardwood that I had - locust, black walnut, red and white oak, sycamore.

The stove always burned well, and at the top of the 42' chimney, there was never more than a wisp of smoke/vapor coming out.   

I always felt like it was a help.   Having it in the smoke stream was like having the damper about half engaged in terms of how the stove "drew", so once it was hot and going well, it all worked great ....

Lannis

[tommy2cyl]

Google Wooden Sun Catalytic vs Non Catalytic Which is Right for You?  Concise pros and cons.  Depends on your mind set & priorities.  The newer from the ground up design catalytic stoves have dealt with many of the drawbacks from the earlier modified non catalytic to catalytic stoves.  Also mentioned in the article the length of the chimney and resultant draw also factors in.  If a longer burn time is critical, greater efficiency and being as environementally conscientious  as possible, then you are a catalytic candidate. 

[tommy2cyl]

Woodstock Soapstone Progess Hybrid.  If I ever need another stove, this would most likely be my choice.  My current Buckstove Insert is built like a tank and unless I move will never need to be replaced. I heat 2200 sq. ft. with it, can fill it at night before bed and has a burn time of 8 hours with ample coals to restart in morning.  Non catalytic, secondary burn with automatic blower.   If I had a different design home and could incorporate a free standing stove, I would look seriously at the Woodstock.

[cliffrod]

An insert or wod stove simply placed in a regular fireplace with a typically oversize chimney flue is a crap shoot in terms of draw.  Masonry chimneys like that are typically cavernous and don't draw well at all.  They're mostly intended to get smoke out of the building.  Limiting airflow into such a chimney even more makes it even more unbalanced.  Adding the liner balances the intake vs exhaust and should help the any convertor or heat exchanger as much as it helps the actual firebox.  As part of an engineered system, the convertor may need to be operational to help the entire unit function as designed. 

Without proper draw, Its hard or impossible for the insert or stove to operate as designed.   This includes a catalytic converter.  Soot and creosote have much to do with condensation & present moisture.  This includes both the system and fuel condition.  Slow draw keeps things cool, which doesn't aid with clearing condensate or increasing the speed of the draw/draft as the flue warms.  A hot burn- always important at the beginning of a cold/cool new burn cycle- to help warm the flue and speed draw to resolve present moisture by both full evaporation & air movement.  Creosote will accumulate more quickly on all interior surfaces without these regular periods of hot burns.  If the convertor doesn't burn hot enough to clear, it will clog and then further slow the draw. It's a lose-lose scenario. 

A not-perfect but easy example that's good for any wood heater to understand.  A fire burning slowly (limited airflow) that's only hot enough to drive off and burn combustible gases produces solid pieces of charcoal.  A hotter fire (at least adequate airflow) more completely consumes the the solids as well as the gases, producing ash with little or no charcoal.  If not cleaned away, Charcoal will accrue and burns well once ignited- just like accumulated creosote (analgous to charcoal) does within a flue.  With your new liner, you may find your draw changes dramatically with only a small amount of creosote build-up.  Burn dry fuel hot regularly like you should and it shouldn't be a problem.

If it were my system and I wasn't changing the firebox, i would fix/replace the convertor comb or research it well before simply eliminating it.   You may learn that the original convertor comb was not as high a quality as what you can now purchase for replacement.  Some older ceramic/firebrick hybrid products were really fragile.

[Aaron D.]

Thanks for the replies.

Yes, the liner has drastically improved draw, which has transformed the heat output.

I actually did read that "which is right" and that was what steered me away from catalyst a bit. Since the insert is somewhat small for whole-house heat it will have to run pretty hot anyway. I may grab another set and see.

Thanks again.

[80CX100]

Glad to hear your re-lining of the chimney is working out for you, I only did that once and my draft was horrible, but that chimney had a very low head height, 12-14' and 2 90 degree bends between the stove and the chimney cap, (later modified to 1 90 & 2-45's, a little better but not much) mine was a crappy set up.

If you don't have one already, good idea to get a manual (google is your friend). I've been around lot's of free standing wood stoves, but this house I'm in now has a built in stove fireplace BIS ll. For the first two years I was here, I hardly got any heat out of it, I didn't realize I was letting it all up the chimney lol.

It was only once I was lucky enough to find a manual that I realized the the 2 air intakes on the unit were completely different, to properly operate my built in fireplace, I open both air intakes to light the fire,,, once it's going I shut off the air intake from the room.Once the fire gets up to a good hot operating temp, I then shut off the fresh exterior air intake, and the secondary burn (catalyst) takes place.

Some of the new style stoves can be very fussy on draft and only like to burn primo well dried quality wood, or that good secondary burn, just won't kick in and keep going well.

I've never been around a ceramic catalyst, I'm not sure what the cost is to replace it, but I think Elmira has a decent rep, it might be well worth the investment? I find it hard to believe that with gentle care and use, anything would only last 2 years. I'd be searching the wood burning fireplace forums to see if anyone has made stainless steel or carbon steel replacement catalysts for your unit, fwiw jmho.

Good luck

Kelly

[Aaron D.]

Hi 80CX,
I have read the manual-I smiled when I read your own thread!

There's a company that sells steel bound catalysts, even for our insert. Elmira is out of the business but I have found sources for what bits I've needed.

Curiosity may get the better of me and see me ordering up a set just to see what happens.