micky wrote:
On Sat, 07 Dec 2013 10:37:20 -0500, "Pete C."
wrote:
micky wrote:
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 did what you said below, and here's what I got
By Delevan,
A = hollow (a hollow cone. All of these are cones.)
B = solid
W = might work where A or B is called for, Delevan says.
By Danfoss
AH = hollow (not HA as I wrote above)
AS = solid (not Hx as I wrote above. Very different nozzles,
almost opposites, yet techs used both in my furnace, just as they used
Delevan A and B.
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.
.75 is gallons per hour firing rate (at 100 psi)
80deg is the spray angle
All of the nozzles used are the same wrt these two things. The
owner's manual confirms the .75.
The letters after indicate the flame pattern eg. solid cone, hollow
cone, more hollow cone, semi-solid cone, etc.
This is what I'm concerned about.
Do a search on "oil burner nozzle cross reference" and you'll find some
charts and pictures that explain the patterns better.
The pattern selection mostly depends on the techs experience and what
nozzles they have on hand.
So if they don't have the right nozzle, they'll use the wrong nozzle??
That seems to be what you are saying.
Not really the wrong nozzle, just a less optimum one.
As to their experience, shouldn't the manufacturer's experience be
what matters?
The firing rate is the most important, and
the spray pattern selected will be based on the size and shape of the
chamber.
But all 3 patterns have been used in my furnace. It's pretty clear
to me that only one was the right one.
All of them are burning the same amount of fuel in the same basic spray
cone. The density of areas within that spray cone is the difference.
Depending on the combustion chamber shape and airflow some patterns may
be better than others, but the differences won't be dramatic.
Aha, over the years, the ID plate in the furnace has gotten dirty, and
I'd cleaned off all the boxes that had letters stamped in them, the
model and serial number, but I see I missed one, the nozzle. Here it
says 0.75 80 Solid. Good to know.
Yet at least two of these guys and more I think before I threw away
duplicates used hollow nozzles. I wonder if that's why it has
smelled faintly of oil when the furnace first comes on, before the fan
starts.
Hard to say. The wrong pattern *might* cause delayed ignition and a bit
of oil smell and "whomp" on startup, but other things like igniter
electrodes a bit out of alignment can also.
Another complicating factor is that some newer burners don't run at 100
psi and instead have high and low firing rates, requiring some
calculation to get the correct firing rate nozzle for the higher
pressure high rate firing.
This is not one of those.
EXT, there is no gas available here.
Extra complaints! (I also noticed after I'd been here a few years,
that the techs were no longer measuring anything. At first they poked
a hole in the flue and measured something, then taped the hole. The
later guy used the same hole. After about 3 years, no one bothered.)
The hole is supposed to be used for combustion gas sampling, smoke
sampling and draft measurements. These are measures of combustion
efficiency and proper venting.
One guy taped the pivoting damper closed. I asked the next guy why it
was taped shut. He didnt' answer me but he took off the tape. None
of these guys were from bargain basement outfits. They all came from
major heating oil vendors in town.
The barometric damper certainly shouldn't be taped off, it's there to
help manage the draft in the chimney.
It sounds like the quality of the techs has deteriorated in your area
If you are interested and have free time, you might check the tech
schools in the area and see if they offer an oil burner service class.
When I took one it was ~$100 for a 12 wk evening class that was
interesting and fun.