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?
80deg is the spray angle The letters after indicate the flame pattern eg. solid cone, hollow cone, more hollow cone, semi-solid cone, etc.
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. The firing rate is the most important, and the spray pattern selected will be based on the size and shape of the chamber.
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.
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.
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.
All of the nozzles used are the same wrt these two things. The owner's manual confirms the .75.
This is what I'm concerned about.
So if they don't have the right nozzle, they'll use the wrong nozzle?? That seems to be what you are saying.
As to their experience, shouldn't the manufacturer's experience be what matters?
But all 3 patterns have been used in my furnace. It's pretty clear to me that only one was the right one.
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.
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.)
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.
Not really the wrong nozzle, just a less optimum 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.
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.
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.
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.
snipped for readability. Only 3 of your lines, plus a bunch of mine.
Ah. Delayed ignition. I can be so stupid at times. Last winter and now the computer is in the basement, and I'm less than 30 feet from the furnace, and I hear it go on and off. I have to pay more attention to the time elapsing between the oil pump going on and the flame starting..... Well it just happened, as I was typiing the previous sentence, and afaict everything except the main fan started at once, but maybe I missed a half second when the oil was pumping and there was no ignition. Furthermore, the smell doesn't happen every time -- I have to pay attention every time now -- and I don't smell it in the basement, only in my bedroom when I'm lying down, my nose about 2 feet from a duct.
Even he didn't use a guage. He may have fiddled with the counterweight, but no guage was involved.
Maybe so. I really should have learned to pin the company down before they sent anyone, that he would use the gauges . Instead I would change companies. (I thought it was too late once he was wrapping up to ask about gauges. He'd do it reluctanty and not well, even if he knew better.
That's a great idea. When I googled, Maine and Massechusettes came up as prior searches! So far only a for-profit technical school with full semester classes, and a wholesaler, R.E. Michel, with 8 hour per day classes, $95 for one day or $350 for 3 days hands-on. I have to talk to them on the phone to see what level they are.
Be sure you have a good working CO detector in the area. While oil smell in the immediate vicinity of the burner is common, if you smell it elsewhere from the ductwork it could indicate a cracked heat exchanger which can let CO into the house.
Unfortunately the public tech schools have been rather gutted by those who think that somehow such skills are obsolete and are beneath their darling hell spawn.
Sometimes a boiler is designed to delay fuel ignition for a few seconds.
My 10 year old Empire baseboard hot water oil fired boiler uses a Beckett burner with a Suntec oil pump that includes a fuel control solenoid that delays sending fuel to the nozzle for about 4 seconds.
Thanks. I have one in my bedroom. I'm the only one here.
Unrelated to this, my previous CO detector woke me up like crazy in the middle of the night. I turned off the furnace, opened the window and couldn't decide when the air was fresh enough to go back to sleep. Plus it was getting colder inside every minute. I guess I took 10 or
15 minutes. The flue was full of soot. Called a furnace guy (who used no gauges) I check the flue for soot once in a while now. The part I can see through the barometric damper is very clean.
I thought I found somethin at Univ. of Md Community College, but it's lost among the tabs right now. My friend took a 3-year course there on massage therapy.
That's not delayed ignition, that's pre-purge. Delayed ignition is when oil is sprayed, but for whatever reason it does not ignite immediately. Pre-purge runs just the blower for a few seconds to establish a draft before it switches on the oil. Pre-purge is usually accompanied by post-purge which shuts off the oil and keeps the blower on for 10 sec or so to clear all combustion gasses out the chimney.
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