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

Ddg551

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?

Legume

You're probably just making your controller work harder.  The air has to get forced out somewhere, I see no advantage, only risk of burning out your fan.

Legume

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

blasting

Legume said:

You're probably just making your controller work harder.  The air has to get forced out somewhere, I see no advantage, only risk of burning out your fan.

Don't have one, so I'm not an authority, but what you say makes perfect sense.  Wonder where it is forcing the air out?  I wouldn't have even thought that would work.

DMW

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

Legume

From @Ddg551 :  

i don't know how to reply to a comment, but it should not make it work any harder than regulating the outlet of the blower and leaving the daisy wheel open.  it might even be better because it allows some compression with all the air in the egg.  regulating the outlet of the guru is instant compression so the blower works harder.  i was actually wondering if it has negative effects on the gasket.

Legume

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

Ddg551

Legume said:

You're probably just making your controller work harder.  The air has to get forced out somewhere, I see no advantage, only risk of burning out your fan.

I don't know how to respond to a reply without using a quote, but it should be easier on the blower (controller) than regulating the discharge to the blower.  I was more concerned with the gasket.  I don't see any smoke out of the gasket, only the door on the bottom, and out of the daisy wheel.  

Jeepster47

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.

Legume

Makes sense I guess.  So what is the low end temp if you hookup the controller but don't run it?  How much air gets around the fan?

Greeno55

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.

Jeepster47

@Legume ... on the DigiQ, I have the Smokeware cap from slightly closed to slightly (1/16") open ... that range seems to work about right.  Might be picking up a little extra venting through the felt seal ... mine's a little thin.

Tonight's cook with the FlameBoss was delayed, so will have to wait until tomorrow to find out.  I'm expecting approximately the same top vent settings for the FlameBoss.

Edit:  Opps, didn't really answer your question.  Don't know hwo low the temp will go if everything is hooked up and the fan is turned off.  Good question ... tomorrow I'll turn the fan off and leave the egg peculating when the ribs are done.

FearlessTheEggNoob

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

alright, I had it backward, assumed the controller regulated up and down, but just up I guess if no damper, so you have to set it up to choke the fire for it to work.

Jeepster47

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

Legume

So, 'splain me this, why is not bad to have the extra load on the fan in this case, but it's bad for my furnace fan if I don't change my filters and create resistance that way?

GregW

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.

Jeepster47

Legume said:

So, 'splain me this, why is not bad to have the extra load on the fan in this case, but it's bad for my furnace fan if I don't change my filters and create resistance that way?

Where's @NPHuskerFL when you need him?

NPHuskerFL

@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.  

NPHuskerFL

@Jeepster47 I would be curious what the actual static pressure is on an egg with the draft motor operating. My guess is that it would be around .08" w.c.  I've never had the urge to throw a manometer on it. 

Jeepster47

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

NPHuskerFL

@Jeepster47Raised indirect but of course. Sheesh amateur  

GregW

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

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

GregW

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.

NPHuskerFL

@GregWDrops Mike. Yep I concur. Funny you bring up modulating for static control. Had a control company remotely 100% close all the economizers on 10 60T DX RTU's building extremely negative as a result and facilities couldn't figure out why the units were showing floodback amongst other anomalies. Good to see yet another HVAC/R guy here.

GregW

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. 

NPHuskerFL

@GregW I'll shoot you a PM so as not to hijack this thread too much.