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To Cat or Not to Cat
Posted: 19 July 2006 04:16 PM   [ Ignore ]
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Hi, am in need of those with Cat expertise but first some background.

I live in a rural area & our nearest neighbors are @ 1/3 mile away as the hawk flies. Our heater is a Fisher MaMa Bear which turns 27 in October & is still in excellent condition.

The stack temperature is kept @ 350-400, save at startup which is 500-600.  Our walls are R-23, the attic R-57, & MaMa sits katy-wompus in a corner that has two 6’ L x 8’ H brick walls that act like an enormous heat sink. Small fires are burned that go out in @ 3 hours if not maintained. The last load is put in @ 10pm & the temp is 60-65 when I get up at 5:30, if the outside temp is @ 20. After re-lighting the temp is 70-75 within an hour.

The wood burned is at least 2-3 years old & stored in an open shed, but the south side is enclosed in glass that spans 24’ L x 7’ H. Such results in a 6% moister content (mc) reading on the sun side of any split that is a year old on my Delmhorst J-Lite moisture meter, while the back end of the split, 22“-24” in length, reads 10-12%. Give that split 2 years & the mc is the same at both ends, 6%. 

Consequently I have stopped cleaning our 13-½’ chimney (7 ½’ Meatalbestos, 6’ of single wall) because the ash accumulation only amounts to a 12oz soda can.

But presently considering stuffing 2 five foot galvanized 26 ga 8” pipe down my Metalbestos sections to ensure that it does indeed last throughout our lifetimes. (About had a heart attack when I saw the price of a 30” Metalbestos section now days.) But more about that in a future post.

As the “energy crisis” goes forward there is no doubt that the Fed/states will require removal of my heater by use of tax credits & or fines. But a $400 - $600 tax credit will not replace my heater which brings me to my question.

From what I have presented above is it possible for you to determine that there would be a major environmental improvement, 60% or more reduction in pollutants, were a Cat installed in my single wall pipe?  If so, please recommend reputable manufacture(s).

If this cannot be determined without testing then is there a DIY kit that can be used to make such a test, or are professionals required? (I cannot seem to find a kit on the net, but then my search parameters maybe wrong.) If a Cat would make a significant improvement in my emissions then I’d like to make the change now so that my wife can see it’s operation & learn what is required to maintain it in the event of my death.

Thanks in advance for your input.

Dave

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Posted: 19 July 2006 04:26 PM   [ Ignore ]   [ # 1 ]
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Dave_1 - 19 July 2006 04:16 PM

Thanks in advance for your input.

Dave

I don’t think there are any commerically availabel cat retrofits these days.

The reason is not because they don’t work, but rather that most older stoves have already gone by the way side so the market is small.

Give the design of a Fischer stove, I would say that a cat installed immediately above the stove might do some good when used correctly. This stove run hot flue temps which would activate it.

Then again, burning technique means a lot also, and if you don’t have heavy creosote problems, you are burning OK.

OH, here’s one at Woodman Associates....so they still do exist. These are good people at Woodman....

Retro Catalytic Link

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Posted: 19 July 2006 06:31 PM   [ Ignore ]   [ # 2 ]
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I’m sure someone’s going to have a heart attack about your idea to put stovepipe down your chimney!

Do you need 8” diameter chimney? Three foot lengths of 6” diameter aren’t much more than $100, are they?

What’s the worry with pollution? Creosote accumulation? Future regulation? Neighbours complaining? You should be able to get a more efficient stove second hand stove without forking out too much.

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Posted: 20 July 2006 07:38 AM   [ Ignore ]   [ # 3 ]
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Craig,

Unfortunately, it appears your right as John, of The Wood Heat Organization Inc., states:

“Retrofit cats used to be available 20 years ago but they didn’t work so they disappeared.”

What made me think that the conversion was possible were statements like the following:

<snip>

“If you have an older wood-burning appliance, consider upgrading to one of the newer appliances certified by the U.S. Environmental Protection Agency (EPA). They include a catalytic combustor that allows combustion gases to burn at lower temperatures, thereby cleaning the exhaust gas while generating more heat. All woodstoves sold today should bear an EPA certification sticker. High-efficiency appliances not only have lower emissions but they are also often safer, since complete combustion helps to prevent a buildup of flammable chimney deposits called creosote.

If you want to retrofit an existing non-catalytic wood-burning appliance with a catalytic combustor, you can buy a catalytic damper. These are available as kits and are usually installed in the flue collar. To monitor the stove temperature after adding a catalytic combustor, you should also install at least one heat sensor on the stove body or stove pipe. Several manufacturers sell retrofit kits, and they may be available from wood stove retailers. They are not appropriate for all types of stoves. Again, be sure to follow the manufacturer’s installation and operating instructions.”

<snip>

http://www.eere.energy.gov/consumer/your_home/space_heating_cooling/index.cfm/mytopic=12570

and

<snip>

“Luckily, there is a course of action available that’s a great deal more affordable than purchasing a complete new wood stove and that still provides much of the efficiency improvement and emissions reduction made possible by these state-of-the-art combustors. There are, you see, over a half-dozen catalytic retrofit devices on the market today, and test results show that they offer significant performance gains over a plain old airtight heater. If you’re in the market for such a device, here are some of the things to look for.

Any retrofit catalyst is a compromise, because the stove that it’s installed in was not designed to insure an adequate supply of oxygen and good mixing of the smoke and oxygen at the combustor. Also, add-on catalysts are often positioned farther from active flames than are designed-in units, so the temperature of gases entering them is generally lower. This means that the add-on (and particularly the external) catalyst may be reluctant to “light off” at the beginning of a burn or after refueling.”

<snip>

http://www.motherearthnews.com/DIY/1984_November_December/Retrofit_Catalytic_Converters

Appreciate your help.

Dave

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Posted: 20 July 2006 08:03 AM   [ Ignore ]   [ # 4 ]
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Dave pressed for time here but from your description I think you also need to take a carefull look and galvanizrs connector 26 gage pipe has no business anywhere near a wood stove.

Just like advertising everything sounds rosey and works In line cats don’t really work you clogg them at startup there is no passage for the needed secondary air feed. As for as producing more heat ? what in the connector pipe secondary burn in the connector pipe ? Connector pipe being 26 ga galvanized with secondary cat light off? Would not be a situation I would want in my home

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Posted: 20 July 2006 09:50 AM   [ Ignore ]   [ # 5 ]
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If you give me dimensions, I could design and fab a relatively simple new baffle that would hold a cat and a bypass gate.  You could fit it in place of the existing baffle and have the best of both worlds. grin

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Posted: 20 July 2006 12:45 PM   [ Ignore ]   [ # 6 ]
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elkimmeg,

Thank you for your good recommendation which I totally agree with.

I apologize for the confusion. I should not have included my remarks since my primary purpose was to get information regarding cat installation, performance, & advice for my type of heater.

However, such was not what I purpose to do with the 2 sections of galvanized pipe. Such are to be installed only inside the metalbestos sections in order to protect their inner walls.

Yes, Metalbestos claims a lifetime warranty & I’m going to ensure that their product does indeed perform that long for our sakes. By not crimping the galvanized sections the galvanized can be stuffed into the Metalbestos & yet still be removed if necessary for inspection & or replacement.

Thanks again.

~~~~~~~~~~~

Matt,

Yes, money is a factor. When I retired the company promised to pay 100% of our health care, now $10k a year comes out of a pension to pay for such. That is a large bite that was not expected.

Was asked by other retirees to go into a class action law suit against the company. I pointed out that the Supreme Court had established a legal precedent against plaintiffs for the benefit of other companies that had been litigated against.
I warned them that all they were going to was get the privilege of feeding the lawyers pot. They went ahead anyway.

Their chance of getting a Supreme Court reversal is about as good as Judas getting out of he!!.

Dave

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Posted: 20 July 2006 01:18 PM   [ Ignore ]   [ # 7 ]
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Dave I can post pictures of what happes to 26 gage galvanised pipe. Save you money and let the original pipe do what it suposed to do. the galvanized sleeve will not last long And that s--ks what they did to your pention

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Posted: 20 July 2006 01:20 PM   [ Ignore ]   [ # 8 ]
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I printed that last time you posted that photo, i have it hanging up next to the galvi pipe on the shelf.

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Posted: 20 July 2006 01:45 PM   [ Ignore ]   [ # 9 ]
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Corie,

Please see my 2nd post on this subject & note the quoted remarks, which were taken from the links posted.

It was because of those remarks that I came to Heath.com in order to determine whether a cat conversion would be environmental significant & how such could be done if so.

From the link that Craig gave, they claim that even if I did install a cat it will not bring the MaMa Bear up to modern EPA standards.

Consequently a cat conversion is a moot point at this time.

However, if I find out later that someone / company has done such & is EPA certified I will certainly pm you.

What dimensions do you need?

Thanks

Dave

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Posted: 20 July 2006 01:54 PM   [ Ignore ]   [ # 10 ]
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I agree that the conversion is a moot point, probably on more than one level.  However, if you wanted to pursue this idea, I would be happy to fab a steel baffle that completely closes off the top half of the firebox.  In this baffle we could fit a cat combustor, and a sliding bypass gate. 

The only thing that concerns me is the size of the firebox and the potential of the stove to produce too much heat.  Don’t know where you live at, but it would be easiest for me to see the unit before I considered building the retrofit setup. 

But again, long run, you’re probably better off picking up a used, EPA certified unit.

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Posted: 20 July 2006 02:06 PM   [ Ignore ]   [ # 11 ]
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Corie - 20 July 2006 01:54 PM

I agree that the conversion is a moot point, probably on more than one level. However, if you wanted to pursue this idea, I would be happy to fab a steel baffle that completely closes off the top half of the firebox. In this baffle we could fit a cat combustor, and a sliding bypass gate.

The only thing that concerns me is the size of the firebox and the potential of the stove to produce too much heat. Don’t know where you live at, but it would be easiest for me to see the unit before I considered building the retrofit setup.

But again, long run, you’re probably better off picking up a used, EPA certified unit.

Hey Corie,
Have you ever thought about installing a baffle into a heatilator fireplace to make it a little more clean and efficient? I was thinking of tinkering with my masonry fireplace by installing Country Flame air tight doors, lining with firebricks, and installing some kind of baffle. But then it would probably be smarter to just put an insert in there.

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Posted: 20 July 2006 02:14 PM   [ Ignore ]   [ # 12 ]
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Messing with heatilators is something I probably wouldnt’ recommend.  The firebox, throat and chimney system are designed for the current temperatures and if you started doing things that greatly increased firebox temps, I think you’d probably end up with a fire in a place you didn’t want it.  That’s just my opinion though.  From what I’ve seen of prefab fireplaces, they were designed on the raw edge of being unsafe as is and anything that greatly changes their operating conditions probably moves them into the region of very dangerous.

Just be patient, I’ll have a multi-fuel dual blower fireplace insert done before you can say jack-rabbit. hahah

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Posted: 20 July 2006 02:25 PM   [ Ignore ]   [ # 13 ]
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Dave, I would be much more worried about the condition of your chimney - i.e. are the interior walls holding out OK - and whether that 12 oz. of creosote might actually be dangerous - than I would be about overzealous government busybodies - at least in rural areas where your neighbours are 1/3 of a mile away. Heck, even up here in Soviet Canuckistan country folks use ancient smoking “airtights” without fear of regulatory intrusion. Drive along any country road in the winter and look at the steel chimneys - well over 1/2 are smoking pretty severely. The torches and pitchforks would come out pretty quick if someone told them they all had to buy EPA stoves.

But seriously, what is the realistic service life for Metalsbestos chimney? I imagine it depends on a lot of factors. I replaced 6’ of chimney last year, it was about 25 years old. It hadn’t seen too much use but according to my father it had withstood 2 chimney fires. It still looked OK, at least to my untrained eye. I got rid of it mostly because I didn’t like it’s ceiling support/stovepipe adaptor box (totally unsafe - see my avatar) and it was an obselete type of chimney (only 1” thick wall) and I couldn’t find parts that would work with it (i.e. a new ceiling support/stovepipe adaptor).

So does anyone have an idea about the expected service life, and how to inspect the condition of a Metalsbestos chimney?

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Posted: 20 July 2006 03:26 PM   [ Ignore ]   [ # 14 ]
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Corie,

The MaMa Bear’s firebox dimensions are:

24” W x 20” D & the height is 16” for the first 9” going from front to the back. But after 12” the interior height is then 22” since this is a two level heater. And the width increases to 26 ½” in this area since there are no fire bricks after 13” off the bottom.

There is an 8” flue that is centered in the back of the heater @ ½” from the top. There is a ¼” thick x 4” D x 12” W flange(?) centered directly under the flue. The distance between flange & flue is @ ¼”. From the bottom to the flange is 13”.

As to your concerns about excessive heat, please read my first post & note that we do not build large & or overnight fires.  The wood that we burn has a moisture content of 6%. That is the truth & proven regularly by my Delmhorst J-Lite meter & the small yearly ash accumulation.

There are two spin knobs on the front doors for fire control & the heater has no gasket. The salesman said that if we correctly loaded & fired it there was no need for gaskets.

I will keep searching the web to see if anyone has had success. If they have & are EPA certified I will contact you for a price.

Thanks much.

Dave

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Posted: 20 July 2006 03:40 PM   [ Ignore ]   [ # 15 ]
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my .02 dave, before you modify any stove beyond the simple cat retrofit, a few points to consider : you may not build large fires or overnight burns, but you open yourself up to all kind of liability situations. If and when you sell your house the new owners might burn it hot and overnight, and possible burn the house down, then they come after you. The next point would be pyroformic carbonization, the wood behind the stove that is safley within current clearances,(modified stoves wont have any tested clearances) over time will carbonize, reducing the combustion point of the wood and ultimatly catching fire. One way around this is to default to the minimum 36” clearance for non listed stoves. This only applies to the stove modification, not the pipe combustor.

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