Guru damper settings

[Amphoran]

I just finished my first cook with the new DigiII, and it is an impressive little device!

I was cooking at 250, and after lighting a couple pices on top with the MAPP torch, I closed the damper on the 10 cfm fan halfway and set the pit setpoint to 250. The top damper was open a quarter turn (and this is the first time I've seen the behavior where it shuts itself! I had to stick a small piece of grapevine in under it to keep it open a quarter turn).

It came up to 250 in about 20 minutes, and held rock stead for an hour. At that point, I set the display to food and left it there so I could tell how things were going from inside. After a couple of hours, I went outside to snoop, and when I changed the display to pit, found that the temp was 265, and fifteen minutes later it was 268. The dome thermometer agreed exactly with the guru.

Obviously, half open must be too much for low temperature cooks. Anybody want to share their experience? Are there any other factors to consider? Should I try 1/4 open?

Thanks,

Mike

[ThreeDJ16]

Re: Guru damper settings

I just finished my first cook with the new DigiII, and it is an impressive little device!

I was cooking at 250, and after lighting a couple pices on top with the MAPP torch, I closed the damper on the 10 cfm fan halfway and set the pit setpoint to 250. The top damper was open a quarter turn (and this is the first time I've seen the behavior where it shuts itself! I had to stick a small piece of grapevine in under it to keep it open a quarter turn).

It came up to 250 in about 20 minutes, and held rock stead for an hour. At that point, I set the display to food and left it there so I could tell how things were going from inside. After a couple of hours, I went outside to snoop, and when I changed the display to pit, found that the temp was 265, and fifteen minutes later it was 268. The dome thermometer agreed exactly with the guru.

Obviously, half open must be too much for low temperature cooks. Anybody want to share their experience? Are there any other factors to consider? Should I try 1/4 open?

Thanks,

Mike

I think your setting problem is in the tophat damper and not on the Guru. I commonly run my Guru at 3/4 open with the 10cfm. But you could not get a grapevine under my tophat damper opening. Usually I open the top till it is free from touching the gasket, then give it a quick twist back toward closed (where it stops under the rotation force is where it stays). That usually works out 1/8 or less (as that last little bit has to be done by hand tightening). The trick with any control device is to let it do all the maintaining of air flow; if natural drafts occur, then the control device has no way of stopping it (though the stoker does have a door that is only open when the fan is on - so I am told). Also make sure there are no other openings (it is amazing how tiny of an air leak can change your temps).

I might also point out to anyone new to the Guru or Stoker, the method I describe above is going to cause smoke to pour out everywhere - this is natural. When you restrict the flow from exiting the tophat (like I do), it has to go somewhere. But in doing this, you will get a much tighter control band so it is worthwhile.

Hopefully I will have a little more insight on the workings of the DigiQ after next week as BBQ Bob is sending me one out.

-=Jasen=-

[Fetzervalve]

Re: Guru damper settings

Hopefully I will have a little more insight on the workings of the DigiQ after next week as BBQ Bob is sending me one out.

-=Jasen=-

I could use some insight on the ProCom, could you send me yours?

[ThreeDJ16]

Re: Guru damper settings

Hopefully I will have a little more insight on the workings of the DigiQ after next week as BBQ Bob is sending me one out.

-=Jasen=-

I could use some insight on the ProCom, could you send me yours?

Hold your breath....I love my Procom. I am very curious of the control characteristic differences.

-=Jasen=-

[Amphoran]

Smoke was coming out of the right rear portion of the joint between top and body.

Mine used to be quite open on the left side, so took off the spring and hinge and reset as best I could; paper is now tight everywhere but right rear, and that's where the smoke came out.

Shutting down the top damper is effectively the same as closing the damper on the fan, so I'll try that next time.

The unit has some very interesting features. The display is just a bit cryptic, but it uses brightness blinking to display the % time the fan is running, so you can check on its operation from a hundred feet away, easily. The display is also large and clear enough that I was able to check the food temp easily from inside the house by taking a glance with my binoculars.

By the way, DJ, I was making your turkey breast recipe! It sounded so good I had to try it - However, after 4 hours, the internal temp was still only up to 165. Did you do that direct? I was using indirect, and I assume that the unit was not fully heat soaked for the first hour or so.

Mike

[rorkin]

DJ is absoloutly right.. The problem is in your top hat setting..

I open the top wide and open the guru damper all the way and even crack the bottom door a little when starting.. Once you have a little overshoot on the temperature , close the guru to about 1/2 or so and the bottom door completely closed..

The top hat should be almost tight. 1/8th of a turn can be enough..for a 250 degree cook Your experience may vary.. but not much.. I know it is hard to believe but the 10 cfm fan will supply the right air flow .smoke will pour out of the KK.. even the top.. Dennis says as well , adjust the top down till you can just feel heat coming out of it..

[ThreeDJ16]

Shutting down the top damper is effectively the same as closing the damper on the fan, so I'll try that next time.

By the way, DJ, I was making your turkey breast recipe! It sounded so good I had to try it - However, after 4 hours, the internal temp was still only up to 165. Did you do that direct? I was using indirect, and I assume that the unit was not fully heat soaked for the first hour or so.

Mike

I will disagree on the first statement as closing the fan damper will make the rising temp response times slower. Closing the top damper will make your falling temp response times quicker (smoke finds a way out under fan power). So fan damper open, tophat closed helps keep it tighter responding in both directions.

Yes, it was indirect and I placed the turkey on shorter after the fire was started - my usual lazy way - hehe. Now, I only used a 1/2 turkey breast that was under 2 lbs. What are you cooking?

-=Jasen=-

[Amphoran]

That first statement was only meant that either increased the back pressure and reduce the flow of air into the cooker; I take your point about the difference in how the whole system responds.

I was doing two half breasts, about 3 pounds each, on the upper grill.

[ThreeDJ16]

That first statement was only meant that either increased the back pressure and reduce the flow of air into the cooker; I take your point about the difference in how the whole system responds.

I was doing two half breasts, about 3 pounds each, on the upper grill.

If it was a sealed tight drum, I would have agreed with you. But doors and gasket areas seal well for me under natural draft; introduce that fan and it all goes out the window. But that's ok as it doesn't effect anything negatively.

Maybe the fact you have two 3lb breast accounts for your time increase. Mine was one 2 lb breast. But you were not far off my times. I turned off the Guru at 165, left in the grill till 170 and then rested uncovered.

-=Jasen=-