Weird fame boss 300 problem?

[PrimeB]

i have a new set up, a Weber Smokey Mountan and the flame boss 300. I have tried 3 times to do an over night brisket cook, each time the pit loses its temp over night. I first thought maybe I did not have enough charcoal or I made a separate error somewhere?? I always end up under cooking the brisket? The Weber gauge and the flame boss read exactly the same initially, I can put the pit temp at 228 and it will stay exactly at that temp, or set it at 223 and it will go to that temp exactly for the first 2-3 hours. Each time I put it at 225, go to bed and I’ll check it in about 4 hours. What happens after several hours have gone by, the flame boss reads 225, but the weber pit gauge reads 205-208. I was trusting the flame boss initially but when I pulled the brisket at 203 per the probes, it was rubbery?? This last time I would wake up every 2 hours and kept raising the flame boss pit temp setting to match the Weber, by the end I was 35 degrees higher on the flame boss than what the Weber showed but the brisket came out right? Does the flame boss require this much attention? OR what am I doing it wrong? Pit probe clamp was 2 “ away from the brisket on the grill grate. Help? I am sure it just user error somewhere, but I am lost?

 

[tom987]

I think the best way to check would be with a good wireless thermometer near where your flame boss probe is. Heat likes to stay high into the lid of the smoker, so I am surprised your seeing it the other way around. You could also wire tie your pit props and flame boss probe together and see if you get a consistent reading. Maybe moving your probe around, you could find a sweet spot.