A couple of months ago, I received an envelope from Yoder which had inside the parts for an engineering change to my model. I also found out that there was one for the 640 as well. I did not know that this change was coming; I did not ask for this change; but, it showed up in the mail box on companies own volition. It was some kind of change which added a fan diffuser to one of the two fans inside the control unit.
Because today is relatively nice, 63 degrees and 19 mph winds, I went outside and with the dog's help, I installed this change. I do not understand the rational or the dynamics of this change, but I do see the results. The biggest impact was in reaching 350 degrees temperature inside the unit within 20 minutes especially when it is 63 degrees and 19 mph winds. The second result is that it is using less pellets. Since I had the hopper full, it hardly made a noticeable decline after one hour of operation. I will have to try and measure this again and provide some verification for myself.
If you are a Yoder owner, and you have not received this change, you may want to give them a call. I am anxious to see how this change performs when the temperature is in the 80's and 90's and the wind is significantly lower.
