Set Temperature Surge

Flyingcolors53

I've used my BGE XL for about 10 years, and on occasion my set temperature will rise above the set point by 20 - 40 degrees.  It seems to take a significant amount of time to get back down to the set point - say 45 - 90 minutes when cooking in the 225 - 300 degree range.  Does anyone have an explanation for this temperature surge that is hard to overcome?

Canugghead

With or without temp controller? If without, do you mean set temp as determined by the daisy wheel and lower vent settings and after temp has stabilised? Does it usually rise after you opened the dome or at random?

Flyingcolors53

It sometimes happens when I start up my fire in the BGE and have set the BBQ Guru DigiQ DX3 fan & controller to a certain set temperature that I am trying to achieve and maintain.  It also happens after opening the lid to spritz ribs and / or other meats.  I can understand how the fire and heat increases after opening the lid for a minute or so; it's just hard to get the temperature back down after such an event.

Flyingcolors53

PS - When using my BGE for long cooks, I always use the BBQ Guru DigiQ DX3 fan & controller to set and maintain my desired temperature.  Really, the only time I don't use the BBQ Guru DigiQ DX3 fan & controller is when I'm cooking steaks and want the hottest fire I can get.

stlcharcoal

Keep in mind that the temp controller probe is sensing 1 cubic inch of air underneath the dome.  The fire moves around, the airflow moves around, the meat has moisture evaporating, all kind of stuff is happening.  Don't worry about.  If you put that probe in your oven, you'd be surprised how much the temperature changed as well even though there's no airflow.

Canugghead

When you start the fire, do you light the entire lump bed, or just one or two spots (my preferred method for low and slow)? The hotter it gets after opening the dome, the longer it takes to come down, smaller fire helps.

Flyingcolors53

I just use one tumbleweed fire started in the center of the lump charcoal.  I let it get reasonably hot and established before I set the BBQ Guru DigiQ DX3 fan & controller to my desired temperature and let the fan pump in the air to raise the temperature to my set temp.

Canugghead

Does the fan pause when dome is opened?

Flyingcolors53

If the dome is open for more than, say 30 seconds, the fan kicks in as the heat within the dome has escaped.  Once up to the set temperature, I try not to open up the dome for more than a few seconds at a time.  Sometimes the BGE seems to continue to heat even after the dome is closed again and the temperature rises above the set point and it's hard to get the temperature back down.

OhioEgger

I recommend trying the Smobot. In my experience, their algorithm for maintaining the temperature is far superior to the others on the market, and I've come to completely trust it. There is no fan, just the natural airflow the BGE was designed for, so there can't be any unwanted push of air to jump your dome temperature up.

stlcharcoal

OhioEgger said:

I recommend trying the Smobot. In my experience, their algorithm for maintaining the temperature is far superior to the others on the market, and I've come to completely trust it. There is no fan, just the natural airflow the BGE was designed for, so there can't be any unwanted push of air to jump your dome temperature up.

A fan cannot push any more air into the the dome than it can let out.  As long as you have the probe and dampers properly positioned, there are not going to be any temperature jumps (even if you open the lid.)  So as long as the chimney damper is set it's going to do exactly what it's supposed to do.  The "natural airflow" is no different...... it's the same marketing of BGE saying their new chimney with the rain guard is somehow better than the Smokeware cap.

Flyingcolors53

Thanks, everyone, for your input.  I appreciate your knowledge and suggestions.

DoubleEgger

Just set your target temp on the controller to about 25 degrees less than your desired temp. Bump up the temp once the egg temp is stable. 

DoubleEgger

Flyingcolors53 said:

If the dome is open for more than, say 30 seconds, the fan kicks in as the heat within the dome has escaped.  Once up to the set temperature, I try not to open up the dome for more than a few seconds at a time.  Sometimes the BGE seems to continue to heat even after the dome is closed again and the temperature rises above the set point and it's hard to get the temperature back down.

There should be an option to shut off the fan when the dome is open. 

Remember the fire triangle. You are introducing a lot of oxygen via the fan and open dome. 

zaphod

DoubleEgger said:

...

Remember the fire triangle. You are introducing a lot of oxygen via the fan and open dome. 

fire tetrahedron. they turned the simple to understand triangle (heat, oxygen, fuel) into the annoying tetrahedron of heat, oxygen, fuel, and "chemical reaction". feh. Stopping a fire used to be described as removing one of the three (oxygen, fuel, heat), which was pretty easy to grok. Now I need to potentially remove the "chemical reaction" whatever that may be.


  

stlcharcoal

zaphod said:

DoubleEgger said:

...

Remember the fire triangle. You are introducing a lot of oxygen via the fan and open dome. 

fire tetrahedron. they turned the simple to understand triangle (heat, oxygen, fuel) into the annoying tetrahedron of heat, oxygen, fuel, and "chemical reaction". feh. Stopping a fire used to be described as removing one of the three (oxygen, fuel, heat), which was pretty easy to grok. Now I need to potentially remove the "chemical reaction" whatever that may be.


  

The word "heat" always confuses people too....."Kindling Temperature" is a better representation.