am I ruining my cat?

[-PB-]

A question for the cat burners... I have a VC encore cat and have gotten into a routine. I work second shift and usually get home around midnight. My main goal is long overnight burns so I can sleep through the night. The wife keeps the stove going during the day so when I get home around midnight i have a nice bed of coals to work with. My question is when I pack the stove tight at midnight for an overnight burn the stove is usually at around 375-400 degrees. After I pack it tight I shut down the air all the way and engage the cat, knowing the temp isnt high ehough for a secondary burn. I am usually too tired or too lazy to wait until the temp climbs to engage the cat like I should.The temp climbs while we are sleeping and holds steady at about 550 most of the night before slowly dropping. Is my cat getting damaged or clogged while engaged at 350-400 before a secondary burn can be achieved? Any suggestions would be greatly appreciated.

 

[Todd]

Only way to know for sure is to check your chimney and cat after a couple weeks. I think if you have really good dry wood you may be ok doing that some of the time, but I wouldn't make it a habit.

 

[Backwoods Savage]

I'd guess you are indeed ruining that cat. Even putting in dry wood, the fire and heat burns or evaporates the moisture. Moisture is the worst enemy to a catalyst. Would it not be better to take an extra 15 minutes and make sure the cat stays good?

 

[thefaf]

I would think, that for the Encore, you don't really have to shut her down at midnight to have it warm enough in the morning. What I'd do, (and have done, I used to work those hours), is fill the stove as soon as I walk in the door, engage the catalyst, and leave the air wide open. Go to the bathroom, brush your teeth, put on your Pj's, and just before you hit the snore shelf, back the air down to halfway or so. The Encore has a thermostat, so if it gets really hot in the wee hours, the air will close up. Betcha you'll have plenty of coals in the morning and the cat will like it much better.

 

[tiber]

I have a VC defiant, and my cats in terrible condition and I'm a burning newbie, but I feel like I can make observations here. You can see inside the stove. If it's too low on the temp and you don't have happy, dancing flames, don't turn on the cat. If the glass is getting ashed, don't turn on the cat. My stove (VC defiant) takes about 10 or 15 minutes after I toss wood in there to go through the whole cool down/get hot cycle depending on the state of the firebox. During that time I can watch the glow go down and the glass get sooted up a bit before it takes off again.

The temp is a good thing to read and be aware of, but you can tell just by looking when you should turn on the cat. Even if you come in, turn off the cat and let the air rip, and go do other house stuff before going to bed, is 10 extra minutes really going to hurt you or the stove to save a $100 cat?

 

[jharkin]

I've got the encore catalytic with the condar digital catalyst temperature probe. Its like $50 or so but it really helped the first year learning when the cat was ready to engage.

What Ive found is that on a cold start if you close the damper before the catalyst is up to temp (500 in the cat chamber) that you will get billowing black smoke out of the chimney. If the fire is burning really hot the cat might eventually light off, but if not all that happens is that you end up smothering it. Note that it can take a good 45 minutes from when the stove top hits 500 to when the cat chamber hits 500.

OTOH, if the stove had been burning on cat all day, after a reload the cat stays warm and you can re-engage fairly soon. But I still give it 15-20 minutes to get good and hot before engaging and turning down the air.

In either case you know you are doing it right when 10min after engaging there is nothing but clear gas or some white steam out of hte stack.



For over night burns, If I left the air control at 1/2 the stove would MELT. On a full load I would typically leave the air control either in the fully closed or pointing straight down (~1/8). Loading at 9pm I would still have coals at 8am.


-Jeremy

 

[-PB-]

Thanks for the advice,
I'll try not to be so lazy and give it some time to heat up before engaging the cat. I know that's what I should be doing but I guess sometimes you don't realize the damage until you have to pay for it.
Thanks again.

 

[fire_man]

I'd guess you are indeed ruining that cat. Even putting in dry wood, the fire and heat burns or evaporates the moisture. Moisture is the worst enemy to a catalyst. Would it not be better to take an extra 15 minutes and make sure the cat stays good?

Dennis: Does this mean you disagree with the comments made by the Woodstock guys at the BBQ that their tests revealed its Potassium in the wood and not moisture or thermal shock that kills the cat? They claim they threw iced logs in the stove and did not degrade the cat, but somehow proved its the potassium. I don't know how to prove this one myself.

 

[Todd]

I'd guess you are indeed ruining that cat. Even putting in dry wood, the fire and heat burns or evaporates the moisture. Moisture is the worst enemy to a catalyst. Would it not be better to take an extra 15 minutes and make sure the cat stays good?

Dennis: Does this mean you disagree with the comments made by the Woodstock guys at the BBQ that their tests revealed its Potassium in the wood and not moisture or thermal shock that kills the cat? They claim they threw iced logs in the stove and did not degrade the cat, but somehow proved its the potassium. I don't know how to prove this one myself.

I've wondered about that myself. Does the potassium cause thermo shock and crumbling or was Woodstock talking about the catalyst metals wearing out from the potassium. Seems to make sense to me if you throw wet wood in a fire it will create steam which will hit that hot cat and cause thermal shock cracking and crumbing. One of the reasons I thought they were going to the steel cat?

 

[tiber]

Well the cats going to get clogged from all of a sudden having a ton of crap fall out of suspension from the thermal shock but that's a clogged cat (or stovepipe) and not a particular problem with the chemistry.

But the chemical reaction in whatever article it was supposed there was a stupid amount of potassium available. Potassium, plus acidic soils (and a lot of acetic acid, or vinegar) produce postassium acetate, CO2 and water. I would guess if you had pines growing next to corn or soybeans and the farmer put down potassium (potash) to fertilize the crops you would end up here, but I don't understand why potassium acetate would be particularly bad for a catalytic converter verus just burning pine and having regular old acetate released from the acidic soil. I would be interested in someone who knows what a cat is made out of explaining this.