Hey all, I have been unpluging the 640s after the few times I have used it and I even give it some time after I plug it in so that the newest firmware for the Fireboard is installed. Okay, so lets have it...
As an update, all is well. I appeared to have shut it down before it completed the warm up process. Yoder believes that the over shoot would have stopped and the temp would have lowered to the default 350. I was advised by Yoder to clean out the ash, turn it on, adjust it to the setting I wanted and let it run. I did just that. I set it to 240 rather than the default 350. The Yoder over shot it by 10 degrees then settled down into the right temp after about 30 minutes. However, after stabilizing at 240 I turned it up to 350 and it over shot it by 50 degrees before starting to settle down. It did settle down after a few minutes. I am not sure if that over shoot of 50 degrees in this case and several hundred on my earlier use (see original post) is normal. Seems a bit high to me. But it did not seem to alarm Yoder.
So what I learned, keep it clean, turn it on, start at a low temp, and let it get stable. Then slowly bring it up if I am going to use a high temp so that the potential to overshoot is reduced.
Yes, the heat diffuser with trap door was worth the money. So easy just to open that trap door and shove the shop vac in to clean it out.
YODER STRONG People! And Big Green Egg, UDS, grill...It's good to have options!