Dutchwest Large Cat. - Am I doing it wrong?

[jotul8e2]

I am new here, but not to woodburning. I started nearly 30 years ago with an Efel (anyone remember those? - the one with the dozen or so strips of glass in the front?). I now have a Dutchwest cat stove from the early 90's out in the shop that was given to me a couple of years ago. I did a rebuild when I got it (new gaskets, new cat, new paint, a couple of new parts) and now have it as my sole heat source for a 2200 sq. ft. (1,100 down, 1,000 upstairs) shop.

This stove is my only experience with a cat combustor. At first I hated it. Now, after two seasons, I can sort of tolerate it. I have two basic issues:

1. Burning seasoned, split oak or hickory it will never get hot enough to light the cat UNLESS I open the ash door along with the damper (I think they call it a "bypass", but its a damper nontheless). This means I must stand by for about 30 minutes while the thing heats up - 15 minutes if starting from coals.
Faqs - Did I open the air intakes wide? Yes. Did I use dry wood? Yes. Do I have a good draft? Yes. Did I give it enough time? Yes, I fed it continuously for six hours once.

2. It appears to allow me to only choose from three heat output modes - too cool for the cat; too hot for the stove; and whatever temperature it chooses to run in between.
Faqs - Do I have a stove top or flue thermometer? No, just the probe type cat thermometer. How hot will it get? 2,000 deg. plus at the cat, if the intake air is not severely restricted.

So, I have found through long trial and error a setting for the primary and secondary air intakes that will usually allow me to establish a burn of 1500 deg. (again, at the cat, not the stovetop) dropping to 800 or so before needing a reload. I never change them anymore as the thing wants to absolutely run away given the slightest opportunity. If it burns all the wood ant the temp drops to low for the cat (like overnight, or when at work) I have to load it up with splits and open the ash door to get it back up to the 500 deg. plus it needs to take off.

On the plus side, runing 24/7 it will hold 65 deg. temperatures out there even when it drops below 10 deg. outside.

Any thoughts or suggestions are welcome.

Oh, I'm also shopping for a stove for the house - but that is another post.

Mark

 

[Todd]

I am new here, but not to woodburning. I started nearly 30 years ago with an Efel (anyone remember those? - the one with the dozen or so strips of glass in the front?). I now have a Dutchwest cat stove from the early 90's out in the shop that was given to me a couple of years ago. I did a rebuild when I got it (new gaskets, new cat, new paint, a couple of new parts) and now have it as my sole heat source for a 2200 sq. ft. (1,100 down, 1,000 upstairs) shop.

This stove is my only experience with a cat combustor. At first I hated it. Now, after two seasons, I can sort of tolerate it. I have two basic issues:

1. Burning seasoned, split oak or hickory it will never get hot enough to light the cat UNLESS I open the ash door along with the damper (I think they call it a "bypass", but its a damper nontheless). This means I must stand by for about 30 minutes while the thing heats up - 15 minutes if starting from coals.
Faqs - Did I open the air intakes wide? Yes. Did I use dry wood? Yes. Do I have a good draft? Yes. Did I give it enough time? Yes, I fed it continuously for six hours once.

15 minutes doesn't sound all that long for reloads. I wait10-20 minutes. You could cut that time down by using smaller splits?

2. It appears to allow me to only choose from three heat output modes - too cool for the cat; too hot for the stove; and whatever temperature it chooses to run in between.
Faqs - Do I have a stove top or flue thermometer? No, just the probe type cat thermometer. How hot will it get? 2,000 deg. plus at the cat, if the intake air is not severely restricted.

So, I have found through long trial and error a setting for the primary and secondary air intakes that will usually allow me to establish a burn of 1500 deg. (again, at the cat, not the stovetop) dropping to 800 or so before needing a reload. I never change them anymore as the thing wants to absolutely run away given the slightest opportunity. If it burns all the wood ant the temp drops to low for the cat (like overnight, or when at work) I have to load it up with splits and open the ash door to get it back up to the 500 deg. plus it needs to take off.

2000 is way too hot. Is this typical with the air all the way down? If so, you may have a leak somewhere or excessive draft. May need a pipe damper?

On the plus side, runing 24/7 it will hold 65 deg. temperatures out there even when it drops below 10 deg. outside.

Not bad, but I bet you can do better if you get that beast under control.

Any thoughts or suggestions are welcome.

Oh, I'm also shopping for a stove for the house - but that is another post.

Mark

 

[webbie]

Early 90's CDW's are not the greatest. I think you have the right idea about shopping for a new stove. Still, it seems to be working pretty good.

That thing was confusing with the separate controls for the primary and secondary....like how the heck is an average user expected to know how to set them?

Keep in mind that the cat is working anytime the temps at your probe are over 600 or so degrees. 1500 is an extremely hot cat and is usually only experienced when fresh wood is giving off lots of gases for the combustor to consume.

OH, Efel stoves...sold a bunch and burned a few:
https://www.hearth.com/econtent/index.php/wiki/Efel_Stoves/

 

[Pine Knot]

It sounds like perhaps that you are waiting too late to close the bypass. On my Dutchwest I have a thermometer on the side door, one on the pipe about ten inches up and of course one at the cat. When refueling I open the bypass and the main air inlet. As the temps. come up I watch the door and the pipe thermometers, when either one nears 500f I close the bypass. At this time the thermometer at the cat will often be below 300f. I leave the main air inlet one half to full open until the thermometer at the cat passes 500f then I close the main air inlet for long burns. My secondary air inlet is set at one turn open and never changed. This procedure gives me cat light off almost every time.
The door and pipe thermometers tell me the stove is hot enough for cat operation, closeing the bypass sends heat and smoke through the cat, warms it up and lights it off.
Hope this helps, good luck

 

[Corie]

Which model Dutchwest do you have?

 

[jotul8e2]

Many thanks for the replies. I do appreciate it.

re: local electric rates - just under $.09 kwh. We could do better with more efficient laundry appliances, but the payback starts to get rather long. Our one big effort at conservation is that nearly all our lighting is fluorescent.

The model is FA264, which they apparently called, simply, the "Large". As noted above, it has both a primary and a secondary air control.

" When refueling I open the bypass and the main air inlet. As the temps. come up I watch the door and the pipe thermometers, when either one nears 500f I close the bypass. At this time the thermometer at the cat will often be below 300f. I leave the main air inlet one half to full open until the thermometer at the cat passes 500f then I close the main air inlet for long burns. My secondary air inlet is set at one turn open and never changed. This procedure gives me cat light off almost every time. "

Pine Knot, that is exactly the kind of help I was hoping for. While one of the world's great cheapskates, I can buy some surface thermometers if it will help. But at this point I am not sure it will as NOTHING I have done allows me to get the temperature back up through the primary air intake alone, once it gets down to 300 deg (again, at the probe) or so. ONLY opening the ash door seems to work. Since it would be hazardous to leave it unattended in that condition, I have to stand there while it gets going. If it is it, in fact, possible to get one of these up to temp using the air controls, what might I be doing wrong? I back the primary all the way open, have tried with the secondary open, closed, and in between, I've checked to make sure the air controls are not blocked. One thing I have not tried is softwoods - I have lots of cedar handy, but that stuff is only slightly less volatile than gasoline.

I do close the bypass as soon as it gets up to 550 deg. or so. And, as I said, I finally got a setting that (usually) keeps the maximum at 1500, so I just leave the air controls at the one setting - primary open 1 and 1/2 turns, secondary open about 3/4 turn. Actually, it just does whatever it wants, depending upon the wood I feed it. Sometimes it maxes out at 1000, sometimes 1500, and even now it still sometimes wanders off to 1800 or more if I don't catch it. Fine tuning within the operating range is, so far, beyond my ability.

It is very easy to tell if the stove is running right - if I can see smoke or smell it, it isn't.

I plan to leave this in the shop. So far I have no wood burner for the house at all, but I'm looking (see thread 14772).

Mark

 

[Corie]

Unfortunately the stove you have really wasn't designed to operate with a catalytic combustor. I know it's in there, but there are multiple design flaws which will make it difficult to operate. I can understand now why you have to have the ashpan door open to get it to fire. If it was a new Dutchwest stove, you wouldn't or shouldn't be having those problems. But these older ones left a lot to be desired including:

1 - No refractory insulation around the combustor.

2 - No refractory insulation in the stove itself.

3 - Poorly distributed secondary (Pre-catalyst) air.

4 - Poorly locating primary air control relative to the firebox layout.

And the list goes on and on and on.

The advice that Pine Knot gave you is good, but just remember I believe he's dealing with the newer, much improved Dutchwest stove, not the older one. I've had the stove you have and I'd experienced all the problems you have as well. That's why I no longer have the stove!

 

[jotul8e2]

Corie - I appreciate you taking the time to look at my problem.

Your comments make a lot of sense. And it does not hurt my feelings as the stove was given to me, so my small investment in the rebuild has already been paid back several times. I got it from a neighbor (he even delivered it) who was letting it rust outside. The only way they could use it in their 700 sq. ft. house was to stand outside and watch it through the window!

If this is the best it will do, so be it. I doubt that I will heat the shop 24/7 after this year (still building cabinets for the house out there, so I need the temperature to be fairly constant), and it is bearable for occasional use.

By the way, that shop is an interesting example of how different buildings function differently. It is conventional stick frame two story, 6" insulated walls, R 60 in the attic, but it has a huge heat sink in the 5" concrete slab and two to four feet of gravel underneath - I insulated the foundation walls before filling. It will take sustained figures in single digits or below to ever freeze inside - if then. But if I let it drop to 40 deg., it will litterally take 48 to 60 hours to warm it up.

Mark