I as well just got a PH. Here are a few questions I've had. I am loading about 3/4 full when I go t bed around 10pm. I get it going, engage the cat, and shut it down all the way. When I wake up there is a bed of coals. I am burning chestnut and various other woods like oak and some birch. I cannot seem to get these longer burns that others talk about. Also, in the manual they say that when you engage the cat you should see dramatic temp rises, which I don't believe I am seeing. My stove seems to hover around 300-350 (I have the thermometer on top of the upper flue plate, i am using the rear exit for the flue). I have never used a cat stove before, so I really don't know what to expect. Will it hurt the stove to shut it completely down for an all night burn?
At what stove top temp are you engaging the cat? I suspect your cat is stalling.
The same thing was happening to me at first. Here is what i started doing.
1) load stove and leave air full open until it is burning very well. 5ish mins
2) shut air about a 1/4 and wait until everything is burning and the stovetop is at least 275. 5ish minutes
3) close bypass
4) let fire get burnig robustly again and let the secondaries start up 2-5 mins
5) close air about another 1/4
6) wait until stovetop is above 315 or so and then shut air completely. 2-5 mins
Whole process takes about 15 mins give or take 5 depending on how robust of a coal bed you are loading on to. Allow a good extra 20 mins if starting from cold.
I went from having a cruise around 350, to having it cruise around 550. If your wood is a little sub par this can have a big impact too.
After i close my bypass and give the fire 5-10 mins of burning , and shut the air fully. I always come back about 10-15 mins later and check the flue temp and stove top temp. If the stovetop hasnt climbed past 350 and the flue temp isnt above 220ish(measured with ir on a liner) then i know my cat has stalled. So i then open the air back up about a 1/4 to 1/2 and let it get going good again for a fewminutes and then shut the air fully and i am usually good from there.
It took my about a year but i finally have it down. Havnt had a cat stall in awhile now. Learned to be patient and let the fire burn good once the bypass is closed for a few minutes.
Edit: oh, once i close the air fully the firebox goes completely black for several hours during which the stovetop temp rises to around 600. Then i will occasionally get a burst of secondaries as it slowly drops from there. I am averagee around 14-16 hour burn times my last few fires. Burn time to me is stovetop above 250