The best way I can explain this cause of this temperature increase/spike just after the lid opening and then closing is because of the temperature drop in the grill when the lid is opened the controller will try to maintain temperature by adding more pellets, when the lid is closed that extra load of pellets has to burn off thus the temperature spike. Best advice I have to try to prevent or lessen this temperature spike is if your going to have the lid open for longer than 30 seconds or so turn the controller down to LO, do what you need to do and reset it back after the lid is closed.I’m having the same problem. I‘m cooking at 225 and when I open, and then close the lid, the temp runs up very quickly. I just adjust the temp down to 200 and then wait for it to come down then i readjust back at 225. Is it possible that the sudden rush of fresh air is causing a flash fire in the ash pot? I was thinking that maybe I have the exhaust vent too wide open. On low and slow cooks should I close the vent a bit?
Nothing. It is common for this PID control. When you open and let the temp out, then close back up, it will often overshoot trying to get the temp back up. Usually it will drift back down to the set level in a few minutes if left alone. At 240 it is only 15* hotter and won't affect your cook. If it does not drift back down, I would be surprised. My 590 does that same thing.My RT 700 is set at 225. Just pulled my brisket out and wrapped it and now my RT700 says it’s overheating. The actual temp is rising above 230-240 when it’s set at 225. Not sure what to do.
Something like a lid switch may be possible and may work to prevent the temperature spikes after lid openings but it would add to the price of the grill, luckily recteq decided to use the KISS method.I wish there was a switch when the lid is opened that would “pause” the PID. Turning the temp down to low helps.
Before you mess with the feed rate, give it a bit of time to see if it corrects. I've seen temp swings when I have the lid open (especially if it stays open for a bit....). The temp will drop when it's open, but then the controller tries to compensate, so you get a spike once you close the lid and you've got more pellets in the pot. I've always seen mine settle back to my set temp pretty quickly.......
Now, if your feed rate isn't set to 30 or 3.0, AND your Bull doesn't recover from this spike, then, by all means, change it.