Quote Originally Posted by tlj000 View Post
I’m missing something here.

Let just say the burner is 100% efficient.
If the load requires 1gph running 24 hrs. that would be 3,336,000BTU/24hrs
Your examples of nozzle and run times and gallons don’t add up to this.
I would also hope that by decreasing the nozzle size you would increase efficiency by lowering the stack temp.

Attachment 341901
My run times were times pulled out of the air as examples. But aren't far off.

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.