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Posted by Jack, CVMS on November 08, 2005 at 01:36:01:
In Reply to: Tune-up problem posted by Sean on November 02, 2005 at 00:32:23:
: The new nozzle was a .75-80w when the boiler has a label calling for a .85-80b. I found out that 80w is apparently a universal one, but would like to know the differences between those nozzles in a bit more detail.
: Thanks for any info about this.
The first number in the nozzle size is the amount of fuel (in gallons) delivered through the nozzle orifice at 100 psi pressure. The second is the angle of the oil spray cone, and the letter at the end denotes the type of spray pattern. The W on a Delavan nozzle designates a Semi-Solid pattern - not quite hollow; not quite solid. The B means is is a solid pattern.
What this means is that the new nozzle will be delivering a little less fuel than the old one was. The AFII has its fuel pressure set at 140 psi, which will cause the fuel delivery to be greater than the number on the nozzle indicates. That is all taken into account by the boiler and burner manufacturers. It is possible that the service technician has had experience with that boiler/burner combination that makes him feel the W type nozzle will give better performance. One one boiler I installed several years ago, that was the case. As to why he downsized the nozzle from the .85 that the boiler specs call for, you would have to ask him. It may be that the smaller nozzle will still provide all the heat you need, but it would seem the technician would have explained that to you.
From what you say about the position of the electrodes, you may have cause to doubt the professionalism of the technician, but at the same time, it isn't possible for someone to make that determination over an internet connection. Glad you were able to get it going reliably, but from the sounds of what you've found, it still needs to be checked by a professional with an analyzer to make certain it will be running as efficiently and safely as possible.