OK, I have the input I was looking for. Thanks all, very much
And now I have the AT100!! I installed the probe and set up the display and all that. Fun! So now I can watch the real temp in there.
I am surprised to see how fast the temp rises when I flip the damper. Well, after all, I am running a bunch of flame into it at first, so no wonder, but from the Encore manual, which says to get the griddle up to 450 and close it, then let it run with open air for 15 minutes or so, I figured it would slowly get up to the 500 or so, which is the bottom end of what will get the cat to fire off. But even if I start with not much coals, and only say, 3 logs, I can flip the damper even before 450 at the griddle, and it climbs right up to 500-600-700 pretty directly, not more than a couple of minutes. Maybe the manual is written for bigger loads, and maybe it's saying it takes 15 minutes for the whole refractory chamber to get up to a temp that will maintain the cat flame? With a good bed of coals I have usually seen it still running at 600 or more, and when I reload it, the wood goes to full flame right away and I flip the damper without a wait, and the temp goes right up to 700-800 in a minute or so.
So, I am happy to see it go up there pretty quick and I pull the air back and it pretty much stays at or above 600 from there.
I know Reckless Guy suggests 1100-1400 but just now that's too high for me. I have a smaller space than most folks with an Encore, and I am concerned that the gaskets are letting at least some air leakage in, so I am not ready to try for more than 3 logs, maybe 4 if it's cold out [by that I mean 10 degrees or less and it's been 20 or more recently]. I actually did try 4 a couple of weeks ago and the griddle temp ran up over 750 for about an hour. The way I have been running it with small loads easily keeps the space at 75, which is OK because at the further end is the entry area and my wife's office, which is a separate zone of the central heat and so the extra heat in the main space spills in there and saves some oil.
I'm doing all this detail only because I've been trying to observe and figure out how my particular situation is going to work. The main, main big question all along has been and is - how can I be confident the cat is firing, so I wont be letting creosote go by. As I said in other posts a couple of weeks ago, I once had a bad chimney fire with an Encore that I was ignorant about, and not running right, and I am dead serious about that issue.
So if I get it up running in the 600-800 range, whether starting cold or with a good bed of coals, can I be confident that the cat is firing and stays firing as long as it stays above 600?
The only reason I have any doubt is that even at 700-800 I go outside and look at the chimney and there is smoke there, it is not just clear wiggly smokeless "heat" coming out. It does take the manual's 15 minutes or so to go clear. So maybe the cat goes into flames right away but is not fully consuming the combustibles until the surrounding chamber gets cooking hot and can eat up every bit of flammable gas?