Oil burner gun operation (C) D Friedman - AudelOil Burner Electrode & Nozzle Assembly: Inspection, Cleaning, Adjustment
     

  • OIL BURNER NOZZLE & ELECTRODES - CONTENTS: Oil Burner Electrode Setting & Oil Burner Nozzle Types, Oil burner nozzle size & pattern selection, & properties. Relationship of oil burner nozzle size, oil pressure, & oil burner BTUH output
  • POST a QUESTION or READ FAQs about oil burner nozzle & electrode function, adjustment, & repair
  • REFERENCES

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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.

We also 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 details (C) D FriedmanArticle Contents

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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.

Oil burner nozzle, Delavan 80A .85 gph (C) D Friedman Oil burner nozzle outlet end (C) D Friedman

Oil burner nozzle specifications (C) D FriedmanIn 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).

Steinen oil burner nozzle guide (C) D FriedmanSo 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. [

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.

Reader Question: how do I convert oil burner nozzle rates in GPH to litres per hour LPH?

(Nov 2, 2014) tking said:
What is the conversion factor to litres per hour? Are they using Britsh Gallons (4.5l) if they are using British thermal units?
Or US gallon (3.78l)

Reply:

This article is using U.S. oil burner nozzle ratings in U.S. gallons per hour.

1 U.S. Gallons (or for oil burner nozzles gallons per hour or GPH) = 3.79 Litres

1 British Gallon = 4.5 Litres

1 British Gallon = 1.6 U.S. Gallons

So if a US-made or US-specified oil burner nozzle is rated at 1.0 gph (at say 100 psi) then it will burn 3.79 litres per hour or LPH.

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 fired heater BTU output estimating tip: If there is no data tag on the furnace or you can't find the oil burner output BTUH you can guess it as follows: Multiply the oil burner nozzle size (firing rate in gallons per hour) x 138,200 (Btus per gallon of No. 2 heating oil) x an efficiency estimate (use .75 for older furnaces and .80 for newer furnaces if you don't have a recent efficiency measurement).

At HEATING OIL USAGE RATE and

at A Total Look at Oil Burner Nozzles [a PDF file] provided courtesy of Delavan we explain the effects of increasing fuel unit output pressure on the actual oil burner nozzle flow rate in GPH of oil.

Reader Question: oil burner nozzle size and spray pattern changes or substitutions

(Nov 22, 2012) Angela said:

can you help I am usein a 1.00/80 A tip oil burner nozzle

(Feb 23, 2013) steve said:

My oil nozzle clogged. It was a .60 gph 70deg. spray angle [spray pattern not stated - ed]. The local store only had a .060 80deg. Is this ok to use.. the furness fired right up,,, but i dont want to do any damage,, thank you

(Mar 18, 2013) Anonymous said:

What would happen if I use a 1.25 / 80 nozzle which my 40 yr old oil burner calls for, verses a 1.00 / 80. I am trying to eliminate the short cycle and short time on which is the problem I've having now. Would adjusting my burner thermostat to the lower end of 0.2 or the higher of 1.4 help? As you can see I'm grasping at straws looking for an answer. Thank you.

(Jan 6, 2013) Nathan said:

Can I use 1.0 80A nozzel instead of 1.0 70A? How is it effect my oil heater?

Reply:

Anon:

  • A small change in oil burner nozzle size - say from 1.00 to 1.10 gph is not a serious problem but you will burn more oil and the oil burner adjustments need to be amended to fire the burner properly and safely.
  • Watch out: a change in the oil burner spray angle is potentially a more serious error that you seem to be avoiding - by staying with the 80 degree angle.

    Changing the burner angle or spray pattern (for example going from an A=Hollow Cone to a B=Solid Cone spray pattern or more important, going from a long narrow 60degree angle to a short wide 80 degree spray angle may make the flame size and shape no longer fit properly in the combustion chamber - leading to improper and unsafe oil burner operation.
  • Changing the heat anticipator in your room thermostat has nothing directlly to do with the choice of oil burner nozzle size.
    See HEAT ANTICIPATOR Adjustment
  • Short oil burner on cycle time can indeed be due to a too-large nozzle, but it could be due to improper control settings, burner adjustments, or other snafus too. We discuss oil burner short-cycling at
    OIL BURNER WONT RUN

Check the data tag on your furnace or boiler to see what the manufacturer says is the acceptable oil burner nozzle size range that is permitted for your equipment, then call a service technician who knows how to service and adjust the system properly.

 

Oil Burner Electrodes - Inspection, Adjustment

Oil burner schematic (C) Carson Dunlop AssociatesThis article series 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.

 

 

 

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.

Beckett oil burner electrode gauge (C) Daniel Friedman, Beckett Corp Beckett oil burner electrode gauge (C) Daniel Friedman, Beckett Corp

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. T

    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

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.

 

Continue reading at HEATING OIL USAGE RATE or select a topic from the More Reading links shown below.

Or see OIL BURNER INSPECTION & REPAIR

Or see OIL HEAT TEXTBOOK

Suggested citation for this web page

OIL BURNER NOZZLE & ELECTRODES at InspectApedia.com - online encyclopedia of building & environmental inspection, testing, diagnosis, repair, & problem prevention advice.

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