Downfiring an oil burner

realolman

duplicate... sorry

realolman

I tried

to make the test as accurate as I could.

Does the test itself seem to be a reasonable field test?

The actual burner run time in minutes and seconds is printed on the chart.

Jim Davis_3

It is a reasonable test, but without the actual combustion numbers it is hard to see how you results are possible. I have an old program which I have to find, but if you can give me the CO2 or O2 readings along with the flue T, might be able to do some actual btu calculations.

12 gal of water equals 100#. 1BTUH = 1#/1 degree increase
100# heated from 100 degrees to 180 degrees equals 80 X 100 = 8000 BTUH

.65gph nozzle @ 140# = .77gph = 107,800btu input or 80,850btu out at 75% efficiency

1.10gph nozzle @ 140# = 1.3gph 182,000btu input or 131,040btu out at 72% efficiency

.77gph based on actual btus should take 6 minutes to bring water up to 180 degrees.

1.30gph based on actual btus should take 3.66 minutes to bring water up to 180 degrees.

These numbers are based on using your listed Flue T. Assuming CO2 or O2 are the same the heat transfer has to be
as calculated above, which is why the chart doesn't make sense.

realolman

this is what

I did this afternoon.

I brushed the flues, inspected the nozzle, and set the burner, using an analyzer.

Then I allowed the boiler temp to fall to 99. After that I ran it, keeping an eye on the oil pressure gauge and checking it with an analyzer.

The results I got for a 0.65 nozzle are attached. The analyzer results are while this test was running.

One thing I am not sure about is the amount of water... for two reasons...

1. the boiler manual says it holds 15.9 gal, but it has a tankless coil, and when I drained it a couple years ago I measured it and I got 12 gal. out of it.

But for comparison purposes, so long as I use the same amount for all tests, it shouldn't matter. Using 15.9 gal gets me over 100% efficient and even I don't believe that.

2. Is it possible since it is not circulating, that I am only heating part of the water that is in the boiler? It sits for several minutes, though, before the temperature peaks, you'd think it'd mix.

...But there again, even though I may not be able to calculate absolute efficiency, I should be able to compare two nozzles.

I am trying to do this as honestly and accurately as I can... hey it's my money going up the stack.