Forced Draft - MORE POWER

[Rick]

200 cfm!?!?

That's not a smoker - that's a FORGE...

[alleyrat58]

200 cfm!?!?

That's not a smoker - that's a FORGE...

Indeed, but I would be looking for a variable speed so that it could handle more or less based on the temp in the smoker. One of the main problems I have with the Guru is that it is on or off. So you are either blowing full CFM or nothing. In my observations it seems almost like the natural draft in the cooker takes time to recover when the pressure is relieved from the forced draft - so you flood your chamber with hot air, then the fan stops spinning, hot air works its way out the top, and then another blast. The blasts of air cause the temp to rise, the Guru slows the blasts causing the temp to fall and we start all over again.

With variable speed there wouldn't be as dramatic changes to the pressure in the firebox. As the smoker heats up, the CFM drops until we hit the sweet spot then a constant pressure could be maintained until refueling the smoker is required at which time the controller would need to adjust. That is kind of where I am stuck with my early prototypes right now. My current prototypes would work great on a system that has a controlled feeder like a Stumps or pellet-pooper, but not so great on a system where you are opening the firebox door while you have food on the cooker.

[Smokeone]

I am intrigued (SP) Alleyrat. I want to see this bad boy come to life.

[Rick]

Have you tried a minion maze for briquettes?
I like what you're doing Ben - keep it up - you'll figure it out...

[alleyrat58]

I am intrigued (SP) Alleyrat. I want to see this bad boy come to life.

All in good time. Just gotta work the bugs out. I also have to work around one of my buddies right now who is studying for the MCAT (test for entrance to medical school). He got a degree in computer engineering then decided he should go to med school and design medical implements for a living - so he's tied up a bit - and he knows everything about the circuitry and micro controller programming. Slow progress, also expensive...

Have you tried a minion maze for briquettes?
I like what you're doing Ben - keep it up - you'll figure it out...

The minion maze is an idea. I am trying to work out a switching system that could be attached to the door of the firebox and door of the smoke chamber to cause the controller to react differently when one is opened vs. the other. Door to the smoker open I would want the fan to slow until the door is closed, then speed up a bit and settle back in the sweet spot. The firebox I'm just not so sure about. Might just have to add lit charcoal all the time. That minimizes the problems anyway...

Guru has a 'door sensor' in at least some of their models (if not all) but it just detects a drop in temp and shuts off the fan. I have two problems with that...
1. in a cabinet style build like mine, the probe is slow to pick up the drop. In most cases by the time it reacts I've already closed the door. Then it sits there for a few minutes until the temp starts to rise again and the process starts over. By this time my fire has started dying a bit and it takes a while for the guru to figure it out.
2. When the Guru detects the door open it cuts air to the firebox, but you still want good clean air for good clean combustion when the door is open, there is just no need for it to overreact to the temp drop and flood the firebox with air.
/rant

[Rick]

a magnetic door switch to a "pause" control would be simple enough.
I would think that whatever intake air leaks past the gate is enough to sustain combustion for the short time the door is open...