While replacing a fuel filter and bleeding an oil-fired furnace (Beckett AFG), I noticed that the nozzle was a .75gph 80 degree solid. The placard on the furnace specs a .75gph 70 degree hollow. Is there any logical reason for that change or should I just replace it with the nozzle specified? Thanks!

Someone might have changed it out if there was a problem with the operation of the unit, or it might have been all the service tech had on the truck. I would go back with what is on the nameplate. Any other nozzle can effect the efficiency and/or reliability of the burner.

I would only trust an oil tech with a combustion analyzer to make changes to an oil fired furnace.

quote:

Originally posted by Excam_Man:
I would only trust an oil tech with a combustion analyzer to make changes to an oil fired furnace.

Exactly. I have seen a lot of oil companies or techs replace nozzles without using an analyzer and also install the incorrect nozzle just because it is ‘close’ and they don’t have the correct one on their truck. Happens all the time.

Thanks, guys.

Excam_man is correct.
The angle change is minor but not a good idea, as the combustion chamber is sized for the 70° angle. The 80° may impinge on the side walls. Spray patterns are more forgiving and about efficiencies. You can change the pattern from the recommended pattern with a combustion analyzer, but why spend the time? Factory already spent the time. I would reduce the fire rate to .65 gph and adjust the air to a less than #1 smoke. Typically doing this will improve efficiency with little output change. Most oil furnaces are over-sized. I hate soot, so I tend to lean the burner somewhat.