My run times were times pulled out of the air as examples. But aren't far off.
Originally Posted by tlj000
1.5 X 14 = 21. 21 X 140000= 2,940,000
1.25 X 16 = 20, 20 X 140000 = 2,800,000
1 X 24 = 24, 24 X 140000 = 3,360,000
The savings of the higher firing rate comes from the off time.
The lowest stack temp is not always the most efficient set up. When the firing rate gets too low, heat transfer rate drops since there isn't enough heat. Unfortunately so does stack, which leads to a false high efficiency reading.