At 650 to 900 are you seeing smoke out the pipe? If yea you are too low
- At 650 to 900 I definitely see and smell smoke out the chimney. I think it is fine to run the stove there but it is definitely not running well or as intended. I would keep an eye out for creosote build up.
- If I had a magic wand and could fix this terrible design I would want my cat at 1000 - 1200F.
You have the option purchasing either if its made for your stove. My stove came with a ceramic, but I run a steel one as of last year. steel lights off easier and doesn't get as hot..
- For the Defiant model 1975 the only cat available as far as I know is the ceramic version. Would love to try a steel one just to see what the effect is, with this stove design it would probably melt the steel cat on the first full load.
For the newer owners who are dealing with over-temping cats.... There is a well known "fix" you should try first (see threads from past years). There are 8 holes at the bottom of your refractory, try plugging some or all of them with machine screws, I use button heads and they fit very nicely. You want them a little loose. This definitely helps to calm things down a bit, although cat light offs will take longer. it is quick and easy and helps, but it is not 100% effective.
If that does not work there are also secondary air feeds on either side of the inner cover, circled in red below. I have plugged those partially / completely with ceramic insulation and that also helps.
None of these have been 100% effective for me and the results vary with wood load, wood quality and I suspect draft levels. Try playing with these areas to tune things for your conditions. If your cat won't get to 1000F on a full load you know you have gone to far.
My personal limits at the moment are (others may feel otherwise)
- At 1250F I have a soft alarm, which means I take action, either increase or decrease primary air or open / close my key damper to change draft. I have mixed results from day to day, sometimes more primary air will bring the temp down, sometimes less air will bring it down, many times nothing brings it down..... I usually wait 5-10 min to gage what the effect was. Many times temps will go down intially and in 3-5 minutes they climb back up again, patience is required....
- At 1450 I have a hard alarm and that's when I throw in the towel and open the cat bypass damper. Exhaust gas temps will rocket north of 950 - 1000F so I close my key damper and close primary air all the way. Then I wait.... sometimes 30 - 60 minutes for the load to burn off some then re-engage the cat and open up the primary air and key damper. Usually this works but sometimes i have to repeat.....
- If things get really bad I will also block off the secondary inlet with a metal plate and a magnet, not too often I have to resort to this. As I wait for the load to cool I swear a lot and search the internet for a new wood stove.....