"micky" wrote in message
...
All these years, I've save the plastic cylinders that oil furnace
nozzles come in, and I finally looked at what they say.

All start with .75 80^ (degrees) but there is a lot of variety in what
comes next. A,B, W, and the other brand's HA and Hx. (I can't find
it right now.)

I had in my mind that the proper nozzle was listed in the owner's
manual, but now that I'm looking, it seems not. (It says 0.75, but
nothing else) How do these technicians decide what nozzle to use,
just whatever the previous guy used? If so, how come there are so
many different containers left behind?

Thanks.

The .75 indicates the gallons per hour that get burned. The 80 degrees
indicate the shape of the flame. The furnace manual should show the degrees
required to get the flame in the correct location in the firebox, and the
gallons per hour most likely adjust the BTU output. When I had an oil
furnace, I started out with a 1 gallon per hour nozzle, but over time the
consumption was reduced down to .85 to economize on the fuel burned and to
meet emissions. Then I changed to a high efficiency gas furnace, and cut my
heating expenses considerably.