Addick9574,
Your troubles read like a duplicate of the issues I've been having. I purchased my EX6 back in Feb 2020 just before all of the quarantine started. We had anticipated having family over for BBQ's this year, but no. Big gatherings discouraged.
I started up the SF just 2x before I started having troubles and smoked up some babyback ribs, once in the spring and another beginning of summer. They were excellent.
Still no family gatherings until the middle of Oct, I started up some ribs and once everything was rolling, headed off on a errand into the city. Came back 4 hrs later and the smoker has stopped at some point after I left. The Display read, Error Code 3. ???? I had no idea what had caused the trouble. Wind maybe ? A storm front was moving in. I shut down the smoker and finished the ribs in the oven. when I cleaned up afterward, nothing looked out of place. I figured it was the wind.
Two days before Thanksgiving we've brined a turkey and have it on the smoker. After about 90 minutes, it is losing temp and up pops error code 3 again. I do a shut down. Wait. Power Off. Power On. Reset the temp. It starts up like a champ, begins heating up, gets to about 160* and starts losing temp again. Error code 3. ??? No wind, it is cold outside, mid-30's. That shouldn't stop it. One more time. Same results. The wife and I look at each other and take the turkey into the house to try and cook it in the oven.
The turkey turned out poor. An unfortunate waste. And while the turkey was in the oven attempting to finish cooking, I'm checking all things in the smoker. Pellets are feeding great. Good fire in the burn cup, temp comes up and then. . . . . and then it errors out; Error Code 3. I was thinking a bad sensor. I appreciate the time you took to post your troubleshooting and resolution. It helps to have some information handy and that you had a resolution.
I have time to call customer service this coming week and see what we can figure out. It was very bad timing to have something fail and the smoker become non-functional when it did.