My Ideal Steel is throwing me a new one. I reloaded on a small bed of coals about 90 minutes ago but only loaded less than a half a firebox full of cordwood. About 20 minutes ago it decided to go to a full cat burn and the cat and flue temp have been coming up ever since. The throttle on the stove is now fully closed but the cat temp is at 1410F and rising about 5F per minute. The flue temp is dammed high but not rising much. Once I hit fully closed, I tried opening the throttle significantly to see if I could coax it into going back to a secondary burn to cool things down but it wasn't interested in being tricked. So when the cat is trying to go China Syndrome like this and the throttles fully shut down, what's the play?
Relax and wait it out. You are still well within safe burning temps. Later, add a flue damper if you want more control on cold days. My understanding is that the manual air control on the IS does not control air to the catalyst, so a flue damper will help control it when you have a stronger draft.
The thing maaaybe is just getting back under control but it's faked me out before. It spent about 2 hours wandering fairly rapidly up and down between about 1370F and 1550F. It's now come down to 1200F and it's holding there, so I think things will be fine.
I wouldn’t worry at cat temps below 1700, stove top temps below 800 and stack temps below 1000 or so. There is a nice buffer between hotter than normal and meltdown. You are nowhere near meltdown at 1370-1550
I know the feeling of knowing it is still ok, but what if it gets hotter??? We address it on the front end of the burn, avoiding coming up to temp really fast. It sounds like you did things right: come up slowly, on a low bed of coals, and with a partial load. That makes me wonder if the splits are very small/fine, or if you have a big air leak. Anyway, I’d try to decide on the full cat burn earlier, before the firebox gets so hot.
I don't have an IS, but a keystone, and if mine goes into full Cat burn, it will sometimes start to climb towards a range I'm not super excited about. Most of the time, it will get hot enough where it will light off, and start flaming again, and the STT cools, along with the Cat. Once in a while though, it will peek past 700, and I'll open the air to see if I can get it to light. If not, I slowly open the bypass a hair, and that usually does it. I don't open it completely, because I've had it ignite the box with a fair amount of force. Enough to blow smoke out of the connector pipe.
I would let it ride. These stoves were built for heat. I would do what beardley reccomended. Crack the bypass open a bit and you should get almost instant ignition and maybe even a slight back puff so be prepared for a big poof if you choose that route.
