Cat Thermal Shock Observations

[leeave96]

I fired-up the Keystone a bit ago - going after a nice clean shoulder season burn. Haven't used the stove much since installing the new SS catalyst combustor, but tonight gives me a bit more experience with it.

Worked the stove top up to about 220 degrees with a mix of seasoned pine and a few sticks of oak for a little extra kick. At 220 deg's, I engaged the combustor and within less than a minute, it's glowing orange. From an internal temperature of just south of 500 degrees inside the stove to who knows what temp the actual combustor is burning. It's hot enough to glow orange and I can see how going from 500 degrees to over 1000 degreees (my guess) on the combustor would cause a lot of thermal shock to a ceramic catalyst in a short period of time.

My old ceramic combustor would go orange pretty fast too.

How quickly does your cat go orange on engaging it? Does it turn to orange slowly or within a minute? It's funny that there is so much smoke upon start-up and on reload, if you are up to light-off temps, I can't see how you could prevent the cat from getting super hot/orange and in doing so causing thermal shock - which I interpret as intense thermal expansion - sort of like throwing a hot glass into freezing cold water - expect something to break.

It's amazing to me how these catalyst combustors hold-up.

Bill

 

[BrotherBart]

Don't know, but the cat convertor in my truck is ceramic and seventeen years old and gets no warmup before engagement and still passes emissions inspections every year.

This is just kind of a jab at folks that won't burn a cat stove but every car they drive every day has a cat in it.

I don't have a cat stove because I am too cheap to buy one.

 

[Todd]

Sometimes my cats glow right away and other times they don't glow til later. Depends on the load and how good it gets going. If I pack it too tight on a cold start it may take a lot longer to get going and if I reload on a good coal bed they take off fast.

Sounds like you might want to purchase a cat probe to play around with. I was thinking about that but it's hard to read from the back. last year a guy here drilled a hole through his top exhaust plate and stuck a probe down dead center of the cat then drilled out the stone so the probe face sit flush. He said it worked great. If I wasn't top vent I'd do the same.

 

[Backwoods Savage]

Like Todd states, sometimes it will start glowing rather quickly and other times a bit more slow. I can't speak about the steel cats though; only the ceramic.

 

[certified106]

Had quite a bit of burn time in on my steel cat before I sold my stove and I would say that at first it would light off really quick at low temperatures but after about two months of burning non stop it started to light off a little bit slower. My advice is to keep an eye on your light off temps as it will start to light off slower after a couple of months. It was still easier to get going than my ceramic cat though. As far as getting it to glow it just depends on the load of wood and the temps. In my experience if put a full load of wood in and didn't' get my cat to light off and glow orange I still had smoke coming out of my chimney it might have been less smoke but I still had some until it would light off.

 

[SolarAndWood]

I always do full loads on top of a hot coal bed. The cat is glowing orange within a minute every time.