Questions For Cat (Stove) Owners...

[Peter B.]

Recently I replaced an old 1" thick catalyst with a fresh 2" model with a finer honeycomb. The stove's behavior has changed somewhat and I'm finding I need to change my fire tending habits a bit as well.

Since my stove is (obviously) not an EPA model, I'm curious about modern cat stove features and operation practices.

So, I guess this is sort of a "cat o' nine tails poll". Any/all answers appreciated.

Thanks.

Peter B.

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1) Do you use a probe thermometer immediately over the cat for temp references?

2) What temp (and where measured) do you typically use for reliable cat light off?

3) Is there a noticeable temp surge on cat light off?

4) How long do you let the cat 'warm up' before closing stove air intake(s)?

5) Once the intakes are closed, does the burn temp remain relatively constant until the coal stage?

6) Does the primary air control close fully (or is it - by design - always slightly open... like many EPA non-cats)?

7) Is there <any> secondary air supply?

8) Do you use a flue damper?

9) Finally, would you opt for another cat stove when it's time to replace your current one? If not, why not?

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[mellow]

1) Do you use a probe thermometer immediately over the cat for temp references?
No

2) What temp (and where measured) do you typically use for reliable cat light off?
400 on stove top with a good roaring fire

3) Is there a noticeable temp surge on cat light off?
Not on mine, but mine is an old cat

4) How long do you let the cat ‘warm up’ before closing stove air intake(s)?
Depending, if I see the cats glowing I turn down the air intakes

5) Once the intakes are closed, does the burn temp remain relatively constant until the coal stage?
Yes

6) Does the primary air control close fully (or is it - by design - always slightly open… like many EPA non-cats)?
Yes

7) Is there <any> secondary air supply?
No

8) Do you use a flue damper?
No

9) Finally, would you opt for another cat stove when it’s time to replace your current one? If not, why not?
Yes, BK Princess when I can budget it.

 

[truckerkev]

wow peter, them where great answers, quick and to the point, mellow, that helped me some also. thank you

 

[Peter B.]

truckerkev:

mellow gave the answers... I provided the questions.

Thanks, mellow.

(By the way, how is the Chesapeake and Eastern Shore? One of my favorite areas of the country.)

Peter B.

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[mellow]

truckerkev:

mellow gave the answers... I provided the questions.

Thanks, mellow.

(By the way, how is the Chesapeake and Eastern Shore? One of my favorite areas of the country.)

Peter B.

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Same as usual, not much changes around here.

Am I missing something here, are you guys talking about adding secondary air tubes to a cat stove?

 

[Backwoods Savage]

1) Do you use a probe thermometer immediately over the cat for temp references?

NO


2) What temp (and where measured) do you typically use for reliable cat light off?

250 degrees. Top center of stove.


3) Is there a noticeable temp surge on cat light off?

Not necessarily a surge but the temperature does go up quite fast.


4) How long do you let the cat 'warm up' before closing stove air intake(s)?

Say what? That cat needs no warmup and the draft control is set about the same time as
engaging the cat.


5) Once the intakes are closed, does the burn temp remain relatively constant until the coal stage?

No. It will stay constant for a long time but then begins to decrease very slowly. Much of this depends upon the wood you have loaded the stove with.



6) Does the primary air control close fully (or is it - by design - always slightly open... like many EPA non-cats)?

We do not have a primary and secondary. There is one control on the draft numbered from 1 to 4. We will set it from .25 to .50 as a regular setting once the cat is engaged.


7) Is there <any> secondary air supply?

NO


8) Do you use a flue damper?

NO


9) Finally, would you opt for another cat stove when it's time to replace your current one? If not, why not?

Yes.

Before buying this stove I had read must of the bad stuff about cats and foolishly believed it. However, we did end up buying this cat stove and love it. We also found all the negative stuff written about cat stoves to be pure bull.

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[Peter B.]

mellow:

As something of an experiment, I added a single 3/4" secondary air tube to my older stove (which also has a cat installed).

The preheating isn't great, my stove internal temps aren't always up to true secondary combustion, and I think I should have at least one more supply tube, but...

I'm convinced it's made a favorable, though modest, improvement... and under the right conditions, I can hear secondary flame ignition, with cat engaged and all air intakes (but the secondary) closed.

Peter B.

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[Todd]

Recently I replaced an old 1" thick catalyst with a fresh 2" model with a finer honeycomb. The stove's behavior has changed somewhat and I'm finding I need to change my fire tending habits a bit as well.

Since my stove is (obviously) not an EPA model, I'm curious about modern cat stove features and operation practices.

So, I guess this is sort of a "cat o' nine tails poll". Any/all answers appreciated.

Thanks.

Peter B.

-----

1) Do you use a probe thermometer immediately over the cat for temp references?
No

2) What temp (and where measured) do you typically use for reliable cat light off?
500

3) Is there a noticeable temp surge on cat light off?
Yes, almost right away the temp starts to rise

4) How long do you let the cat 'warm up' before closing stove air intake(s)?
On my stove I engage with my air setting on #1 and will tweak it down from there as needed depending on how the fire looks and what the stove temps are at.

5) Once the intakes are closed, does the burn temp remain relatively constant until the coal stage?
My stove climbs at first, then maintains a certain temp for maybe 2 hours, then slowely drops.

6) Does the primary air control close fully (or is it - by design - always slightly open... like many EPA non-cats)?
fully close

7) Is there <any> secondary air supply?
This stove has one air control, but there is a metal plate above the glass air wash with holes that supplies the cat with secondary air. It is all contolled with the one sigle lever.

8) Do you use a flue damper?
Yes, my draft is too strong at times.

9) Finally, would you opt for another cat stove when it's time to replace your current one? If not, why not?
I don't know, I have my eye on the Harman Oakwood, Blaze King, and PE T-6 and they all have different combustion systems.

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[Highbeam]

At least one cat stove, the VC dutchwest one, has a seperate control for secondary air supply up near the cat.

 

[Peter B.]

For clarity's sake my question...

4) How long do you let the cat ‘warm up’ before closing stove air intake(s)?

... is based on my own use. That is, I typically end up closing my air intakes once the cat has (definitely) lit off... but it seems to require at least a few minutes to 'settle in'. If I clamp down the air controls too soon, temps will slowly fall rather than stabilize or rise... so I wait a bit.

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Backwoods Savage and Todd: Thanks for your replies.

CZARCAR: Thanks as always for your commentary.

Peter B.

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[karri0n]

Doesn't seem like the answers could be accurate... cats need secondary air, and if you could close the air ALL the way, the fire would go out completely.

 

[Peter B.]

karri0n:

I'm guessing that some air supply channels may be very well hidden on some of these stoves, and that it may not be readily apparent where air enters the stove. Also, <any> stove nowadays will have some sort of glass airwash, which may serve to 'feed' the cat more effectively than the fire itself.

But I'm only guessing...

Peter B.

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[mellow]

I can cut all the air to my stove if I wanted to, and have done so before just for tests using my front air intake.

I posted this before but it is a video of a 1994 Ultimate Heating Systems BV large fireplace insert that uses secondary air with a cat.
http://www.youtube.com/watch?v=gcBzJxbGJrg

 

[mellow]

I am not exactly sold on secondary air tubes in a cat stove. From what I can see from mine is all the flammable gasses are being used by the cat, I see no smoke out of my chimney once I engage the cat, if there was something left unburnt I would think I could see it, but maybe not.

I have posted this before to, it is a blaze king in action and shows the difference with the cat engaged and not engaged, pretty cool, seems to me that a secondary air tube wouldn't add any more efficiency.

http://www.youtube.com/watch?v=dwNYI6ME7kA

 

[karri0n]

karri0n:

I'm guessing that some air supply channels may be very well hidden on some of these stoves, and that it may not be readily apparent where air enters the stove. Also, <any> stove nowadays will have some sort of glass airwash, which may serve to 'feed' the cat more effectively than the fire itself.

But I'm only guessing...

Peter B.

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That's more or less what I was getting at. The fire still needs to have at least a little bit of air, even in a catalytic combustor. Those air inlets are probably nor affected by the air control.

 

[Peter B.]

mellow:

Durn... and me on dialup... no can do YouTube.

So what does the fire do when the intake is closed? Is it just smoldering or are there visible flames?

I would extend the poll to include the same question to other cat stove owners...

Peter B.

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[mellow]

That's more or less what I was getting at. The fire still needs to have at least a little bit of air, even in a catalytic combustor. Those air inlets are probably nor affected by the air control.

On my stove all air comes in through the front air inlet, I CAN cut all air to my stove by sliding it shut, when the cat is engaged and I want the stove to idle around 400 deg. I just barely have my air inlet open so it feeds a trickle of air to the fire.

 

[mellow]

I guess I will now have to climb up on the roof and stick my CO detector by my cap and see if it reads anything with the cat lit.

 

[karri0n]

Use a canary, no batteries required.

 

[mellow]

So if I drop the canary down the liner and it comes back up we are good right?

 

[Peter B.]

Frankly, I'd use a starling and spare the canary.

Almost every spring, at least one starling gets past the chimney cap and most of the way down the flue. I have no compunction about intrducing a little CO to its lungs. Easier to deal with dead than alive.

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mellow:

If you actually do take a CO reading, I'd be curious what you find.

Peter B.

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[21acrewoods]

Do those cats really cost $300 to replace?

 

[Peter B.]

Do those cats really cost $300 to replace?

No.

Peter B.

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[karri0n]

Some. They range from 75-300, but you're getting a really terrible deal at 300, and should probably find another dealer or go online.

 

[truckerkev]

my cat was $257, blaze king oval