Traeger lost fire

[pokey]

It was 1:00 am and I was 15 hours into smoking a pork butt at 225*. I'd gotten past a rather long stall by raising the temp to 250* at 12 hrs. The probe was saying the IT was a little over 185* and climbing, so I was thinking I was maybe an hour or so away from finishing, when the fire went out. I hadn't quite hit optimal pulling temp, but called it a night. The roast was fine, but I'm wondering about my equipment.

When I went to clean up, there was a mound of unburned pellets pouring out of the firepot. Clearly the auger had kept working after the fire had stopped. I cleaned her out and and fired her up and the pellets dropping into the firepot started to smolder, so the igniter is apparently working fine. So, what happened?

I always start with a fully vacuumed firepot. Might ash have built up during a cook to the point that newly dropped pellets can't get to the igniter? I've cooked this long before, though not for a while. (I've been experimenting with sous vide pre-cooking, so I've been doing shorter smokes.) I'm using Lumberjack Competition Blend which, according to reviews on Amazon, generate more ash than others, but I've been using them for more than a year and vac the firepot before every smoke.

It's a 10 year old Traeger Lil Tex. A couple of months ago I started to experience temp fluctuations. Turned out the firepot had rusted out and the new holes were bad for air flow. I replaced it and things seemed to get back to normal. I also replaced the igniter, not because it was acting up, but because it was old and while I had it apart, I figured I might as well. Based on what I'd read, if replacing the firepot hadn't fixed the problem, it was possible that the controller had gone bad. (Apparently this can happen after a decade of suffering through the weather.) But things seemed OK, until last night.

So, do I just figure this is an anomaly and do nothing? Or do I start thinking about pre-emptive maintenance?

Thanks in advance for your thoughts.

 

[bregent]

Might ash have built up during a cook to the point that newly dropped pellets can't get to the igniter?

No, the igniter is only energized during startup - once the pellets are lit it is not needed anymore. Flameouts can occur for a few reasons. A pellet bridge in the hopper may prevent pellets from falling into the auger, long enough for the fuel to burn out. Then if the bridge collapses, pellets will be fed into the cold fire pot.
I think a more common cause is temp swings. The controller can get into an oscillation mode when temps swing way above, and below setpoint. During these swings, the fuel burns out quicker than pellets can be fed. That's the advantage of having a more sophisticated controller than the simple old Traeger controllers.

 

[pokey]

Thanks for the info. How might a more sophisticated controller have helped? I had started looking into controllers in case I needed to replace the one I have, but stopped when I thought I'd solved the temp fluctuation problem. What does one look for?

 

[radio]

I would start by asking Traeger about the issue.
The same thing happened on my GMG and it wass the thermal sensor that malfunctioned.

 

[pokey]

I hadn't thought of the sensor. It's original, and while I've cleaned it, it's definitely looking its age! I think I can check that.

A pellet bridge that later collapsed will be impossible to prove one way or the other! I may never know.

Thanks.

 

[radio]

I hadn't thought of the sensor. It's original, and while I've cleaned it, it's definitely looking its age! I think I can check that.

A pellet bridge that later collapsed will be impossible to prove one way or the other! I may never know.

Thanks.

I would call Traeger and pick their brains. I would also do a couple of test runs with no food to see if it acts up again and would use a remote thermometer to keep tabs on what the temps are doing.
It has to be either the sensor or the control board, but my money is on the sensor