I have a BIS ultima Stove , I put a thermometer on the black pipe above the fire box, I dont run it too hard but I am seeing temps at that point of 550-600. I was told its too high but if you read the manual they don't say anything about safe operation temps.
Is that a magnetic thermometer on the surface of single wall stove pipe? Or double wall? Or a probe thermometer into the flue gas?
It's been years since I dived into the temps. I recall the temp should be taken 18" from the top of the stove. I use a probe thermometer. I keep it in the 400-700 F range. 550 is a good temp I think.
Can you move it up another 6-8"? Assuming you have single wall pipe, internal temps are generally considered to be double the external, 18" up. So yeah, 1100-1200*F is definitely high! 4-500* would be considered more normal on most stoves, once you have the stove happily settled into a new load.
If you're running at 1100+ F continuously, you're stressing the pipe. How tall is the flue from stove top the chimney cap? You're loosing a ton of heat out of the flue at these temps. Maybe your draft is high due to a tall chimney leading to that heat being sucked up. A key damper might help them.
You should be able to get good temperature control with the air lever. If the temperature doesn't come down when you reduce the air control then the door gasket could be worn out and leaking air into the fire. Or the door could be misaligned. Looking at the manual, the air control pulls out for boost mode, as well as moving left and right for air control. Are you pushing the lever in to turn boost off?