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YS640 Left-Tight Temp Difference

PostPosted: December 14th, 2015, 11:29 am
by rfeustel
Hello,

I thought I saw a thread on this but can't seem to find it. I did my first cook (pulled pork) this weekend and I have a question. I'm getting a temperature difference of 50 degrees left to right on the 640. No matter what I do with the diffuser, I can't seem to decrease that differential. In fact, pushing the damper in too far (meaning closer to the fire box with only a few inches before fully in) seemed to increase the differential a few degrees, making the chimney side hotter.

I'm using the redicheck probe, run thorough a probe port which I did tighten to close around the probe wire. the probe was placed a few inches inside the right edge of the diffuser, using the stock grill clip and placed in the center of the grill. I ran it with the chimney up against the "dongle", noticed that when I tightened it down the top edge tipped in a little, so I pulled it out a little. That didn't make a difference (did both ways for a few hours). I got this difference during the cook, and also during my burn in with an empty grill.

Dual hood thermometers are reading less than the probes, of course, but confirm the differential.

Before I start trying to "fix" my setup, I just thought I asked what is the difference I should be seeing?

I've seen Yoder Hebrs checklist for what to check in the setup. The only thing I think I have wrong is maybe my foil wasn't wrapped tight enough around the diffuser (using the new diffuser with the door in place). But I got a similar differential during the burn in and just thought it was because the grill was empty.

Responses appreciated.

Re: YS640 Left-Tight Temp Difference

PostPosted: December 14th, 2015, 7:12 pm
by Yoder_Herb
Check this out.

Pull the damper out to the right (chimney side) and push it back in 4 to 5 inches. Mine stays in this position all the time.

Not sure where your probes are located in the pit, but they need to be lying directly on the grate and for the 640, at the 11" and 22" point from the hopper wall. If you are reading temperatures past the end of the diffuser, all bets are off, as you will see a large disparity because of the chimney exhaust.

Ditch the foil and see what happens.

Re: YS640 Left-Tight Temp Difference

PostPosted: December 15th, 2015, 8:09 pm
by rfeustel
Thanks, Herb. I'm getting more probes so I can do that. When you say lying directly on the grate, you mean don't use the grill grate clips that come with the probes - actually lay them down on the grate, right?

Also, I assume position them on the centerline of the grill?

Definitely will ditch foil.

I'll report results. Advice much appreciated.

Re: YS640 Left-Tight Temp Difference

PostPosted: December 17th, 2015, 11:15 am
by Yoder_Herb
Yes, directly on the grate.

Yes, centered front to back.