Hello everyone,
First off let me thank everyone for their time in developing a great tool
. The heatermeter has a ton of potential for making great BBQ extremely easy to do. I hope to apply some of what this forum has done for wood/charcoal smokers and apply that to pellet smokers. I have read a few old threads about people kicking around the idea of doing this project and there were some good thoughts, so last night in an effort to better understand my smoker, I did some reverse engineering.
I have a Jim Bowie grill, made by Green Mountain Grills. I have had it for a few years and have made some terrific BBQ on it. The part that I feel needs improvement is the temperature control as well as the extra bells and whistles that come with a heater meter. The stock control has a digital readout that displays pit and target temperature. To control that temperature it uses a combination of two fans and an auger that pushes the pellets into the fire. These two fans are wired in parallel with one in the pellet hopper (to force air down the auger tube to prevent pellets in the auger from catching fire) and the other supplying air to the fire box (similar to a stick burner).
Pit Fan:
Auger Motor:
https://lh4.googleusercontent.com/-.../9w3iOIhIppk/w408-h725-no/20150323_182252.jpg
https://lh6.googleusercontent.com/-.../WQHTAXvvsKA/w408-h725-no/20150323_182307.jpg
In addition to these elements there is a glow plug that ignites the fire during the startup sequence. Using my multimeter I was able to determine how the controller starts the smoker up.
Time Discription
0:00 Power switch on, auger motor receives 120v, glow plug receives 120v, fans are off
1:00 Auger turns off, glow plug remains on, Fans receive 120V
2:00 Glow plug turns off, controller switches to normal operation (Fans and auger modulate as necessary)
Once the pit is operating, it will switch between two modes. One for heating the smoker, and the other to cool down. From what I can tell there is no middle ground.
1. Pit temp lower than set temp - Fans will run at 100% (120v), auger motor will run intermittently. I think there is an internal repeat cycle timer that manages this. From my best judgement it looks like about a half second on, with a 3 second off period.
2. Pit temp higher than set temp - Fans reduced to 30v and auger motor does not run.
Hopefully you can see how there is room for some improvement here. After looking at the other threads, I think the easiest this to do is to replace the fans with 12v fans and connect them to the HM as designed. Then install the servo switch John Hulsman found (https://www.dimensionengineering.com/products/battleswitch) to the damper control output. This would then feed a 12v repeat cycle timer to drive a relay that would then feed the auger motor (as Gary Graham suggested). This would take care of the normal operation of the smoker, but doesn't do anything about the glow plug. I am thinking this can be done manually to start, or perhaps wire it through another timer when I turn the unit on. I am planning on ordering some parts later tonight to get this started, but would appreciate some feedback on other ways to make it work.
First off let me thank everyone for their time in developing a great tool
. The heatermeter has a ton of potential for making great BBQ extremely easy to do. I hope to apply some of what this forum has done for wood/charcoal smokers and apply that to pellet smokers. I have read a few old threads about people kicking around the idea of doing this project and there were some good thoughts, so last night in an effort to better understand my smoker, I did some reverse engineering.I have a Jim Bowie grill, made by Green Mountain Grills. I have had it for a few years and have made some terrific BBQ on it. The part that I feel needs improvement is the temperature control as well as the extra bells and whistles that come with a heater meter. The stock control has a digital readout that displays pit and target temperature. To control that temperature it uses a combination of two fans and an auger that pushes the pellets into the fire. These two fans are wired in parallel with one in the pellet hopper (to force air down the auger tube to prevent pellets in the auger from catching fire) and the other supplying air to the fire box (similar to a stick burner).
Pit Fan:
Auger Motor:
https://lh4.googleusercontent.com/-.../9w3iOIhIppk/w408-h725-no/20150323_182252.jpg
https://lh6.googleusercontent.com/-.../WQHTAXvvsKA/w408-h725-no/20150323_182307.jpg
In addition to these elements there is a glow plug that ignites the fire during the startup sequence. Using my multimeter I was able to determine how the controller starts the smoker up.
Time Discription
0:00 Power switch on, auger motor receives 120v, glow plug receives 120v, fans are off
1:00 Auger turns off, glow plug remains on, Fans receive 120V
2:00 Glow plug turns off, controller switches to normal operation (Fans and auger modulate as necessary)
Once the pit is operating, it will switch between two modes. One for heating the smoker, and the other to cool down. From what I can tell there is no middle ground.
1. Pit temp lower than set temp - Fans will run at 100% (120v), auger motor will run intermittently. I think there is an internal repeat cycle timer that manages this. From my best judgement it looks like about a half second on, with a 3 second off period.
2. Pit temp higher than set temp - Fans reduced to 30v and auger motor does not run.
Hopefully you can see how there is room for some improvement here. After looking at the other threads, I think the easiest this to do is to replace the fans with 12v fans and connect them to the HM as designed. Then install the servo switch John Hulsman found (https://www.dimensionengineering.com/products/battleswitch) to the damper control output. This would then feed a 12v repeat cycle timer to drive a relay that would then feed the auger motor (as Gary Graham suggested). This would take care of the normal operation of the smoker, but doesn't do anything about the glow plug. I am thinking this can be done manually to start, or perhaps wire it through another timer when I turn the unit on. I am planning on ordering some parts later tonight to get this started, but would appreciate some feedback on other ways to make it work.