I have been cooking butts with the daisy wheel closed while using the guru.

I should say, try one with the daisy wheel wide open and let the controller do its job.

The daisy wheel isn't airtight. Probably too tight for a natural draft, but certainly leaky enough to work just fine with a controller.

I don't have a controller either, so just guesswork for me.

Legume said:

I should say, try one with the daisy wheel wide open and let the controller do its job.

Don't do that.

The controllers can only blow air into the egg to raise the temperature.  No check valve at the blower, so air will leak into the egg when the blower stops.  Leaving Ugly Daisy open will mean the temp goes up well beyond the low-n-slow range, just like opening the bottom vent on a manual cook.

Lowering the temp with a blower installed involves choking the top vent down so that the "natural temp" without the blower working is below your set point.

The ideal setting is with the top vent closed such that it forces the blower to work about 20 ~ 30% of the time.  I used to think that 10% was okay until the temp took off on me during one of my cooks.

Bottom line is the blower raises the temperature and the top vent lowers the temperature.  Overworking the fan will cause no harm ... computer fans run 100% of the time ... and stalling the airflow through a fan will actually reduce the current draw.

I've done mine with the damper on the blower housing unit shut 2/3 and the small openings on the daisy wheel cracked a bit.  Holds the 250 I set it to without issue at all.  Can doesn't even work all that much.

Ddg551 said:

hey guys, I was just wondering if anybody has used this technique.  It cooks an 8 pound butt in about 6 to 7 hours and it turns out so juicy and perfect.  I run the egg at 225 and wrap around 160-165 and pull at 203.  I will let it chill in a cooler for 2-4 hours.  Is letting it blow with everything closed off bad for the egg?

I suspect it holds the humidity within the egg higher, as long as you keep the dome closed as much as possible.

@Legume ... thought the same as you until I had some experience with one. Finally had a "duh" moment and then it all came together.

I have a Stoker, But had a Guru before.
I suggest cracking the daisy wheel 1/8 to no more than 1/4. I'm talking about rotating the wheel, not sliding it open.
If I close off the vent on the Stoker it will over pressurize the egg and smoke will leak out anywhere it can.
Closing the damper too much won't damage the fan, however it will make the temp difficult to control.

@Jeepster47LoL. Two different types of motors.  One designed for a higher static pressure therefore it doesn't exceed the rated F.L.A. capacity. Furnace with a clogged air filter causes it to increase static pressure which can cause the blower to exceed the F.L.A. 
I'm no Bill Nye.  

Hmmm ... manometer ... would you cook that direct or indirect?

I'm in commercial HVAC and have been for 30 years.
Fans, like pumps only pull current when actually doing work. (Not counting the energy required to simply cause the motor to rotate without load) Static pressure in systems that utilized variable air flow (VAV) boxes in years past utilized dampers on the inlet to the fan housing on the suction side.
The modulation of these dampers controlled the static pressure in the duct.
When the dampers are mostly closed the current is lower. When the dampers modulate open to increase the static pressure in the duct the current increases. (or in the case of the egg, the daisy wheel is open)
It really doesn't matter if we are talking about inlet vanes on the suction side of the fan or a dirty filter. Anything that reduces the airflow also reduces the work being done by the fan and thus the current is lower.

Water pump flow is regulated by closing the valve on the discharge of the pump. This lowers the water flow and thus the current lowers. This is counter intuitive to the way most people think.

The modern way to control both air duct pressure and water flows is to utilize variable frequency drives (VFD) These drives give precise speed control and same considerable energy at part load conditions.

I hope this sheds some light on fan electrical current.

 

Dobie said:

Its just a PC fan adapted to blow air into a glorified flower pot, dont over think it. 

That sums it up nicely.

I work primarily on controls now. As you have seen controls guys can cause unbelievable trouble and damage to systems when they don't understand the mechanical side of systems.
I always wanted to build my own temp control for the egg. I found it difficult to find parts that would fit together and not look like a huge science project gone wrong. Not to mention it cost more to build it than simply buy a Guru or Stoker.
Are you at a service company or a large building/campus?
I work for a mechanical contractor.