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 Oil Burner Electrode & Nozzle Assembly: Inspection, Cleaning, Adjustment
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InspectAPedia tolerates no conflicts of interest. We have no relationship with advertisers, products, or services discussed at this website.
Oil Burner Nozzle Electrodes: here we explain how to select & install an oil burner nozzle, we describe different oil burner nozzle firing rates & spray patterns; we discuss the setting of the gap and position of oil burner ignition electrodes, and we discuss how to diagnose oil burner electrodes or nozzle problems, how to inspect, clean, and adjust oil burner nozzles, electrodes, and air turbulators used on heating oil burners found on residential & light commercial oil burners.
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Oil Burner Electrode Setting & Oil Burner Nozzle Types, Selection, & Properties
Oil Burner Nozzle Types, Flow Rates in GPH, Spray Patterns, Selection Guide
 Oil burner nozzles have the job of spraying heating oil into the combustion chamber in a spray pattern of the right size and shape to properly fit the equipment and to assure a fine spray that in turn assures as complete combustion of the heating oil as possible. Oil burner nozzles get grubby during use, but actually they are a beautiful and precision-made and sophisticated device.
Cut to the chase? OK so if you don't know a reason to change, install the same oil burner nozzle type that was already on the burner.
Our oil burner nozzle photo at left shows you what an oil burner nozzle looks like. We are holding a Delavan 0.85 gph (oil flow rate) oil burner nozzle.
The "80A" marking on another nozzle facet (photo below left) defines the spray angle (80 degrees) and spray pattern (A). At the right side of the nozzle assembly you can see the sintered bronze filter that protects the oil burner nozzle orifice from clogging. But of course if oil reaching this point is dirty (say you never installed that oil filter or it's leaking debris), this final filter will clog.
Our third oil burner nozzle (below right) shows the outlet end of the nozzle and you can see that there is a stainless steel insert with a small opening that forms the spray pattern for this device. Before manufacturers started using these beautiful steel inserts the entire oil burner nozzle was made of brass - and the spray opening would wear during the heating season, leading to a bad spray pattern. This is not the case any longer and the nozzle below will have no wear problems provided it is replaced during annual maintenance.
 In an emergency oil burner texts suggest cleaning this filter or even removing it and trying to de-clog the nozzle orifice. We don't recommend those steps.
First off a new nozzle is not expensive. Second using a wire in the nozzle orifice will likely damage it and ruin the spray pattern.
When the service company buys oil burner nozzles (in huge quantities in their case) each oil burner nozzle comes in a (usually color-coded) plastic container such as the one we show at left, indicating the gph rating and the nozzle angle and spray pattern.
The number of oil burner nozzle sizes and spray patterns is quite large because the nozzle properties have to accommodate not only models of oil burners themselves but more critically, different sizes and shapes of combustion chambers in boilers, furnaces, and water heaters, and different combustion chamber designs (wet base, dry base, for example).
 So how do we choose the right oil burner nozzle? We need to know the equipment specifications for the oil burner nozzle recommended by the manufacturer.
You can find that in the installation and service manual for the oil fired device, you can ask the manufacturer, or you can use a nozzle guide such as the W.M. Steinen Mfg. Co. Nozzle guide - a book that lists literally thousands of oil burner nozzles for every application. We show an example page from Steinen at left. [Click to enlarge this or any image or photo found at InspectApedia.
You will see that for each brand of oil burner, or boiler, furnace, or water heater, and for each model within that brand, there is a listing of the required oil burner nozzle. These oil burner nozzle specifications will show:
- The gph capacity of the oil burner nozzle. This is the nozzle firing rate - the number of gallons per hour of No. 2 heating oil that the nozzle will pass, assuming that the oil burner fuel unit is set to 100 psi. At higher psi settings such as are often used today, the actual oil consumption rate for a given nozzle, say 0.85 gph, will actually be higher (and can be read from a graph or table of oil pressures and flow rates.) In fact we used to drop the nozzle one size, say from 0.90 to 0.85 gph when setting up the pressure from 100 psi to say 110 or so.
- The nozzle spray angle. Generally in a larger deeper combustion chamber, that is one that is "longer" with respect to the direction of spray of oil, we use a more narrow (and longer) spray pattern. In a shorter or smaller combustion chamber, to keep from impinging heating oil in the combustion chamber rear wall (too much impinging means incomplete combustion) we use a more wide-angle spray pattern, perhaps a 60 degree model.
- The nozzle spray pattern: there are at least nineteen different spray patterns possible. The basics are hollow vs. solid spray patterns (hollow means the core of the spray contains fewer droplets), and various combinations of these parameters. Each spray pattern is designated by a letter stamped into the nozzle on one of its facets. So the nozzle whose data we showed above, a Delavan 80oA means the nozzle sprays at an 80 degree angle with spray pattern "A" which we know is hollow. Here is an oil burner spray pattern legend from Steinen.
Table of Oil Burner Nozzle Patterns & Properties
| Oil Burner Nozzle Spray Characteristics |
Nozzle Spray Pattern Code |
| Hollow |
A, C, H, NS |
| Solid |
B, P, R, S |
| High Velocity |
HV |
| Semi Hollow |
CM, SH |
| Semi Solid |
PLP, SS |
| Special Design |
Q, W, |
| Special Design - anti rumble |
AR |
| Hollow or Solid |
H or S |
| Extra Solid |
ES |
| Extra Hollow |
EH |
Notes:
The duplication in codes accommodates not only a range of oil burner nozzle manufacturers or OEM specifications, but also some special features. For example, the Special Design AR nozzle is designed to minimize oil burner flame noise or rumble. One of our favorite nozzles was the Monarch™ AR series for just this reason. |
Oil Burner Electrodes - Inspection, Adjustment
 This website answers most questions about central hot water heating system troubleshooting, inspection, diagnosis, and repairs. We describe how to inspect, troubleshoot and repair heating and air conditioning systems to inform home owners, buyers, and home inspectors of common heating system defects. Our sketch (above) shows how an oil burner gun atomizes and sprays heating oil into the combustion chamber - Audel Oil Burner Guide. Also see OIL BURNER INSPECTION & REPAIR.
Also see HEATING OIL USAGE RATE where we explain oil burner nozzles in additional detail.
The articles at this website describe how to recognize common oil-fired heating appliance operating or safety defects, and how to save money on home heating costs. Readers should see HEATING SYSTEM INSPECTION PROCEDURE wHere we explain an organized approach to inspecting the entire heating system, beginning outdoors, continuing indoors, and ultimately in most detail in the boiler or furnace room. Also see CHIMNEY INSPECTION DIAGNOSIS REPAIR for details of chimney inspection, diagnosis, and repair, including blocked chimney flues, chimney backdrafting, leaks, and odors from flues.
Oil Burner Electrode Settings Guide & Measurements: Oil Burner Ignition Electrode Gap & Positions
An oil burner adjustment template provided by Beckett Corporation and shown just below summarizes the adjustment of the ignition electrodes & their positioning for Beckett oil burners.
And for eight oil burner head designs the template recommends oil burner nozzle firing rates (in gallons per hour or gph) and spray pattern or style.
As you will read below, there is a very large array of oil burner nozzles and spray patterns provided by a variety of manufacturers.
SNAFUs to watch out for when cleaning & adjusting the oil burner nozzle assembly
- Loose, damaged, misaligned oil burner electrodes (use a simple oil burner nozzle gauge or a small steel rule to see that the position of the oil burner electrodes in their gap apart, their distance above the oil burner nozzle orifice, and their distance forward or backwards relative to the face of the oil burner nozzle are according to the manufacturer's specification.
Often that data is imprinted on a tag right on the oil burner itself. Our photos (above) show how a stainless steel oil burner nozzle and electrode adjustment gauge is used to align the oil burner electrodes, courtesy of Beckett Corporation, a supplier of oil burners including the model shown at the top of this page. The nozzle and nozzle adapter and oil delivery tube are to the right of the gauge face and you can see an electrode in line with the upper + mark in the sketch at right.
- If you try to adjust or replace the oil burner nozzle, electrodes, or electrode ceramics (this is a job for a trained service technician, but an amateur can clean the outside of these parts if working with care not to disturb the adjustment). We also discuss oil burner nozzles and heating oil delivery rates and pressures at HEATING OIL USAGE RATE.
- Be careful not to over-tighten or damage the brass nozzle-end fittings - the connection between the oil burner nozzle itself and the brass oil burner adapter. Early in our oil burner service experience we thought it was great to make these parts as tight as possible. The result was damaged threads on the oil line to which the nozzle adapter was mounted, or damaged threads between the nozzle adapter and the nozzle itself - leading to oil spray leaks, improper firing, and having to replace these parts damaged by heavy handedness.
- Be careful not to break the ceramic insulators on the oil electrodes
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Frequently Asked Questions (FAQs) about Oil Burner Nozzle Assemblies: nozzles, electrodes, settings, cleaning, diagnosis, repair
Question: Every time my oil furnace fires I can smell raw heating oil/diesel smell from my chimney.
Every time my oil furnace fires I can smell raw heating oil/diesel smell from my chimney. It may last up to 5 minutes. No smell in the house. The furnace gets serviced every year,new filter,new nozzle and cleaned. - Joe. 10/10/11
Reply: Improper oil burner operation, unburned oil, or bad draft - watch out for a puffback
Joe,
I agree that you should not smell heating oil when the equipment is running. Because you describe the smell as not continuous, just at start-up, I suspect a dirty system that needs cleaning and service. Or you could have a dirty chimney and bad draft.
Most likely you've got a system that is not running properly and is stinking up things at start-up. Once strong draft is established and the system is up to full operating temperature (typically 5 minutes), the draft improves and combustion may improve enough to keep going. But the system is not running properly.
Watch out: if this condition continues the risk is a puffback that can damage the equipment and blow soot around the building.
A blocked or dirty chimney or lack of combustion air or other causes could be present - ask your heating service company manager to send a technician who will diagnose and fix the problem. It sounds as if the usual annual service procedure has not been sufficient.
That's no surprise. During the heating season the techs are overworked and over committed and sometimes will just clean the system without taking the time to diagnose an actual problem and fix it.
Question: Sometimes my oil burner won't re-ignite
I have an aero burner on my hot water furnace. Starts and runs perfect most of the time. Every once in a while it will not re-light I press the reset button, it might run perfect for a week or two, then one day it will not light Press button again,starts right up and runs perfect, maybe for two days or two weeks again, then all of a sudden it will not light Any suggestions what to look for. - Joe Daye 12/3/11
Reply:
Joe, take a look at the oil burner diagnostic suggestions beginning at OIL BURNER INSPECTION & REPAIR. Usually when a system is limping along as yours is described, the operating problem is going to get worse. I'd look for an air leak in the oil piping, a dirty oil burner, a clogging filter, a draft problem.
Question: I kept my oil furnace running for two hours - would that damage the electrodes or transformer?
I kept the oil furnace running continuous for about two hours, then it stopped running by itself. I pushed the reset on the stack control, it ran for a few seconds then kicked off. Did I burn out the electrodes or transformer by running it non stop? - Bob 2/9/12
Reply:
Bob:
No. Running a furnace non-stop for two hours should not itself damage the equipment. On the coldest windiest day of the year in a poorly insulated home an oil burner might run almost continuously for hours. Something else is wrong.
Question: In cleaning my oil burner assembly I bumped the electrodes - I'm not sure if there is a problem
I cleaned my nozzle and bumped my electrodes but I think I got them set back where they go. I put them back in. I started my furnace and now it runs fine. It runs till it gets to proper set thermostat setting then kicks off. The relay control cell seems a little hot at the back closest to furnace. I checked to see if working properly by pushing red switch when running and when pushed down it stops and let up it continues.
Is this normal the heat at back of gray box? Also could you do damage if your electrodes are a hair off? I don't know I am just paranoid now! The flame constantly runs with motor till it heats to proper temperature then kicks off. - Mark Freed 2/20/12
Reply:
Mark:
If there is an oil burner adjustment or cleaning or draft problem, one result could be back pressure in the combustion chamber. The oil burner may start and run, but back pressure sends heat back up the burner tube where it can overheat (and destroy) the ignition transformer and it may also heat up the primary or cad cell control mounted on the same assembly.
If the electrodes are a "hair" off - that would be about 25 to 50 microns, and not important. But if the electrodes are more than 1/16" off of proper position (see the Beckett template above), or if the ignition transformer is failing, adjustment and replacement may be in order.
Question: Our oil burner only ignites if the door is open. What might be wrong.
We have replaced the electrodes and nozzle on the furnace. It will only light with the door open and stay going after you close the door - seems like it is not getting enough air. What could be the problem? - Simone
Reply:
If you mean that the door to the boiler room (or furnace room) has to be open for an oil burner to work, that suggests it's air starved - we need about 1 sq. in. of air intake into a small utility room per 1000 BTUH for oil fired heating equipment - so a 90,000 BTUH oil heater would need 90 sq. in. of unfettered air intake opening. If you add louvers and screening the sq. in. requirement is increased. Take a look at COMBUSTION AIR and COMBUSTION AIR for TIGHT buildings
But lack of combustion air usually leads to sooty operation and the oil burner going off on reset, or worse, loss of heat.
The bit about "... stay going after you close the door " is baffling. If we don't have enough combustion air to ignite then we shouldn't have enough combustion air to keep going. I figure you need a service call from an expert heating service tech who will check the condition of the burner, combustion air setting, cleanliness of the flue vent connector and chimney, the draft, and a few other parameters.
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Technical Reviewers & References
Related Topics, found near the top of this page suggest articles closely related to this one.
 Carson, Dunlop & Associates Ltd., 120 Carlton Street Suite 407, Toronto ON M5A 4K2. (416) 964-9415 1-800-268-7070 info@carsondunlop.com. The firm provides professional home inspection services & home inspection education & publications. Alan Carson is a past president of ASHI, the American Society of Home Inspectors. Thanks to Alan Carson and Bob Dunlop, for permission for InspectAPedia to use text excerpts from The Home Reference Book & illustrations from The Illustrated Home. Carson Dunlop Associates' home inspection education products include
- The ASHI-adopted Home Inspection Training Program, and Commercial Building Inspection Courses
- The Home Inspection Home Study Course, and publications such as
- The Home Reference Book, a reference & inspection report product for building owners & inspectors.
Special Offer: Carson Dunlop Associates offers InspectAPedia readers in the U.S.A. a ten percent discount on any number of copies of the Home Reference Book purchased as a single order. Just enter HRBUS10 in the order payment page "Promo/Redemption" space. Note: InspectAPedia.com ® editor Daniel Friedman is a contributing author.
- The Home Reference eBook, an electronic version for PCs, the iPad, iPhone, & Android smart phones
- Home Inspection Report writing materials, including the Horizon Software System that manages business operations, scheduling, & inspection report writing using Carson Dunlop's knowledge base & color images. The Horizon system runs on always-available cloud-based software for office computers, laptops, tablets, iPad, Android, & other smartphones.
- The Illustrated Home illustrates construction details and building components, a reference for owners & inspectors
- Beckett Corporation, 38251 Center Ridge Rd.,
North Ridgeville, OH 44039 440-327-1060 Email: sales@beckettcorp.com supplies residential and commercial oil burners for boilers, furnaces, and water heaters - see www.beckettcorp.com/
- A Total Look at Oil Burner Nozzles, available from Delavan Fuel Metering Products, a reference guide for oil burner service technicians, Delavan Spray Technologies, Fuel Metering Products Division, PO Box 969, Bamberg SC 29003, Tel: 800-982-6943 or 803-245-4347, ( Delavan is a division of BF Goodrich); web search 12/30/2010, original source: http://www.delavaninc.com/pdf/total_look.pdf
Note & disclosure: when we (DF) were servicing oil burner equipment, Delavan nozzles gave us such excellent results, especially using hollow cone spray patterns in solving combustion problems, that this brand was our standard stock-item on our truck. Other brands of oil burner nozzles are of course also of excellent quality. It is the proper matching of nozzle size and type and spray pattern to the equipment that is critical.
- Fuel Nozzles for Oil Burners, Technical Aspects of Applications, E. O. Olson, Chief Engineer (deceased)
Delavan Fuel Metering Products Operation,
Bamberg, South Carolina, Delavan Fuel Metering Products, a reference guide for oil burner service technicians, Delavan Spray Technologies, Fuel Metering Products Division, PO Box 969, Bamberg SC 29003, Tel: 800-982-6943 or 803-245-4347, ( Delavan is a division of BF Goodrich); web search 12/30/2010, original source: http://www.delavaninc.com/pdf/Fuel_Nozzles_for_Burners.PDF
- Inspection Procedures for Oil-Fired Heating Systems Detailed step by step approaches for inspecting complex systems]
- Oil Tanks - The Oil Storage Tank Information Website: Buried or Above Ground Oil Tank Inspection, Testing, Cleanup, Abandonment of Oil Tanks
- Audels Oil Burner Guide, Installation, Servicing, Repairing, Frank D. Graham, 1940's edition (obsolete). Updated versions of this guide are available in various editions, 1947, 1950, 1955, 1958, 1959, 1962, 1965, 1967, and at prices from around $3.00 to nearly $70.00 - useful for simple, clear, but not current, explanation of how heating equipment works. The original retail price was $1.00. Used copies are available at Amazon.com
- Domestic and Commercial Oil Burners, Charles H. Burkhardt, McGraw Hill Book Company, New York 3rd Ed 1969.
- National Fuel Gas Code (Z223.1) $16.00 and National Fuel Gas Code Handbook (Z223.2) $47.00 American Gas Association (A.G.A.), 1515 Wilson Boulevard, Arlington, VA 22209 also available from National Fire Protection Association, Batterymarch Park, Quincy, MA 02269. Fundamentals of Gas Appliance Venting and Ventilation, 1985, American Gas Association Laboratories, Engineering Services Department. American Gas Association, 1515 Wilson Boulevard, Arlington, VA 22209. Catalog #XHO585. Reprinted 1989.
- The Steam Book, 1984, Training and Education Department, Fluid Handling Division, ITT [probably out of print, possibly available from several home inspection supply companies] Fuel Oil and Oil Heat Magazine, October 1990, offers an update,
- Principles of Steam Heating, $13.25 includes postage. Fuel oil & Oil Heat Magazine, 389 Passaic Ave., Fairfield, NJ 07004.
- The Lost Art of Steam Heating, John Doe [Dan Holohan], 516-579-3046 FAX, at Amazon.com and the InspectAPedia bookstore
- Principles of Steam Heating, Dan Holohan, technical editor of Fuel Oil and Oil Heat magazine, 389 Passaic Ave., Fairfield, NJ 07004 ($12.+1.25 postage/handling).
- Principles of Home Inspection: Steam, Electric & Wall/Floor Heating, Carson Dunlop, at Amazon.com and the InspectAPedia bookstore
- "Residential Steam Heating Systems", Instructional Technologies Institute, Inc., 145 "D" Grassy Plain St., Bethel, CT 06801 800/227-1663 [home inspection training material] 1987
- "Residential Hydronic (circulating hot water) Heating Systems", Instructional Technologies Institute, Inc., 145 "D" Grassy Plain St., Bethel, CT 06801 800/227-1663 [home inspection training material] 1987
- "Warm Air Heating Systems". Instructional Technologies Institute, Inc., 145 "D" Grassy Plain St., Bethel, CT 06801 800/227-1663 [home inspection training material] 1987
- Heating, Ventilating, and Air Conditioning Volume I, Heating Fundamentals,
- Boilers, Boiler Conversions, James E. Brumbaugh, ISBN 0-672-23389-4 (v. 1) Volume II, Oil, Gas, and Coal Burners, Controls, Ducts, Piping, Valves, James E. Brumbaugh, ISBN 0-672-23390-7 (v. 2) Volume III, Radiant Heating, Water Heaters, Ventilation, Air Conditioning, Heat Pumps, Air Cleaners, James E. Brumbaugh, ISBN 0-672-23383-5 (v. 3) or ISBN 0-672-23380-0 (set) Special Sales Director, Macmillan Publishing Co., 866 Third Ave., New York, NY 10022. Macmillan Publishing Co., NY
- Installation Guide for Residential Hydronic Heating Systems
- Installation Guide #200, The Hydronics Institute, 35 Russo Place, Berkeley Heights, NJ 07922
- The ABC's of Retention Head Oil Burners, National Association of Oil Heat Service Managers, TM 115, National Old Timers' Association of the Energy Industry, PO Box 168, Mineola, NY 11501. (Excellent tips on spotting problems on oil-fired heating equipment. Booklet.)
- Developing your X-Ray Vision - 6th Ed. The Science of Building Inspections - advanced home inspection techniques including "The Limits of Vision," "Inattentional Blindness," "Invasive Inspection Methods," "Missed Defects," & "Contextual Inspection," "Termite Inspections," "Moisture & Building Water Entry," © Daniel Friedman 2006-1987
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Books & Articles on Building & Environmental Inspection, Testing, Diagnosis, & Repair
 The Home Reference Book - the Encyclopedia of Homes, Carson Dunlop & Associates, Toronto, Ontario, 25th Ed., 2012, is a bound volume of more than 450 illustrated pages that assist home inspectors and home owners in the inspection and detection of problems on buildings. The text is intended as a reference guide to help building owners operate and maintain their home effectively. Field inspection worksheets are included at the back of the volume. Special Offer: For a 10% discount on any number of copies of the Home Reference Book purchased as a single order. Enter INSPECTAHRB in the order payment page "Promo/Redemption" space. InspectAPedia.com editor Daniel Friedman is a contributing author.
Or choose the The Home Reference eBook for PCs, Macs, Kindle, iPad, iPhone, or Android Smart Phones. Special Offer: For a 5% discount on any number of copies of the Home Reference eBook purchased as a single order. Enter INSPECTAEHRB in the order payment page "Promo/Redemption" space.
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- Carson Dunlop, Associates, Toronto, have provided us with (and we recommend) Carson Dunlop Weldon & Associates' Technical Reference Guide to manufacturer's model and serial number information for heating and cooling equipment
Special Offer: Carson Dunlop Associates offers InspectAPedia readers in the U.S.A. a 5% discount on any number of copies of the Technical Reference Guide purchased as a single order. Just enter INSPECTATRG in the order payment page "Promo/Redemption" space.
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