What exactly does the numbers on an oil burner nozzle mean?
In particular what is the letter designation stand for?
What is the difference between:

.65 80 A
and
.65 80 B



Thanks

First, while HVAC (Heating, Ventilation, Air Conditioning) is my primary trade, I am not an expert in oil. Here in Norhtern Ohio we use Natural Gas. Here and there and oil burner and have service techs that specialize in Oil.

OK. Here is what my books tell me.

.65 is the gallons of #2 fuel oil at 60 degs. F the nozzle delivers.

Next there are three types of nozzles. Solid cone, Semisolid cone and Hollow cone.

Each one of these is use for a particular spray pattern and angle. My guess is the 80 is degrees of angle of the cone. This is usually between 30 to 90 degrees.

Now the letter. Now I am at a loss. This could be the hollow, semi, or solid cones. If you have two nozzles marked like that, there may be a third. A, B, and C. Just a guess. May be a fuel grade nozzle change or use with a differant grade of oil. Like #1 or #2 fuel oil.

If you have oil, your supplier will be more then happy to tell you exactly what this is all about. He would also be the best person to recommned someone to service and check your system. Don't just call some Heating/Cooling contractor. They will take you money and say everythings OK. Unlike natural gas, this needs to by on a regular bases as the air/fuel mixture is important and can change without you noticing it. It can save you fuel and that means $$$.

Let me quote one thing from my book.
"Nozzles should be removed and replaced with a special nozzle wrench. Never use adjustable pliers or wrench."

Hope that helps.