Oil Burner Tests & Adjustments: How to Measure & Set Oil Burner Combustion Air & Smoke Levels
OIL BURNER SMOKE TEST - CONTENTS: Guide to oil burner operating tests: Bachrach or Bosch Smoke Numbers. How to measure oil burner smoke level to evaluate system efficiency and operation. What is the correct smoke level for oil burners. How to Diagnose Oil Burner Noise, Smoke, Odors. Diagnose & repair oil burner soot, puffback, rumbling, hard-starting.
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Oil burner smoke test which in turn reflects combustion air & temperature adjustment are necessary for safe, efficient and reliable oil burner operation: this article explains and illustrates oil burner smoke testing - a key step in oil burner adjustment for proper operation. An oil burner flame that is too smoky soots-up the heating system leading ultimately to a no-heat call and a clogged furnace or boiler or water heater. An oil burner flame that "looks very clean" may in fact be running too hot, wasting fuel, increasing heating costs, damaging equipment, or perhaps evenm unsafe. This article describes how we measure the oil burner smoke level and describes the proper smoke settings.
This 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.
The basic measurements made by any competent oil heat service technician include the stack temperature, draft, smoke level, and carbon dioxide level (OIL BURNER CO2 TEST).
These data tell us whether or not the equipment is properly adjusted and operating safely and economically. Here we explain how we measure the Bachrach or Bosch smoke numbers - a slightly subjective evaluation of the level of smoke or "soot" found in oil burner exhaust flues.
One of these most basic tests performed by an oil heat service technician is the "smoke test" using a strip of filter paper and a pump to sample the oil burner exhaust, measuring the level of smoke in the exhaust.
Our photo (left) shows a traditional smoke testing pump (the black cylinder with a handle at its right end) used for decades. This equipment was produced by Bachrach, an oil burner test equipment manufacturer.
The technician allows the oil burner to reach normal operating temperature (perhaps after it has been on for five minutes),
A clean white strip of filter paper is inserted into the end of the smoke testing pump.
The nozzle of the smoke tester is inserted into a 1/4" diameter hole in the flue vent connector pipe, typically just a few inches above the top of the oil-fired heating boiler or furnace.
The pump is operated
The filter strip is removed and the "blackness" of the sample spot is compared with a scale that rates the soot level. An experienced oil heat service technician simply looks at the black or gray spot on the filter paper.
Watch out: as we have written in several articles, it is impossible to do a good job cleaning and servicing oil fired heating equipment without getting dirty. But if you put your sooty fingers all over the filter paper before or after conducting a Bachrach / Bosch smoke test, then soot from your hands will get onto the filter paper and you may mistake a 0 smoke reading as a 1 or 2 level smoke. Don't touch the smoke sample test area with your dirty fingers.
Zero-level smoke in a Bachrach / Bosch test is actually "too clean" for most oil burners, and means that there is too much air entering the oil burner, causing the burner to operate too hot, and sending too much heat (and thus the money the homeowner spent on heating oil) up the chimney.
The correct smoke level is just a "trace" of smoke on the filter paper, a level of 1 is good.
A smoke level of "1" or "2" is normal. In our oil burner smoke test results photo (at left) you can see four smoke test samples. Sample #1 is certainly too dirty, sample #2 and sample #3 are a bit high, though we might accept sample #3. Sample #4 is just slightly above zero and is a good setting.
Watch out: sorry for the labels in our photo at left: Don't mix up our sample numbers #1 - 4 with smoke level values = 0,1,2,3, etc. A smoke level of 0 means there is no black soot visible on the filter paper.
The Bachrach or Bosch smoke number scale ranges from 0 (no detected smoke) to 9 (solid black). In addition to using the hand operated smoke pump illustrated here, some electronic combustion analyzers can also produce a smoke level number. [Click any image or table to see an enlarged, detailed version.]
Higher smoke levels indicate that the system is operating too "dirty" or smoky. High levels of soot in the oil burner exhaust mean that the system will deposit soot more rapidly inside of the furnace or boiler heat exchanger, interfering with heat transfer into the building heating air or water, and thus increasing system operating cost - meaning higher heating bills and more frequent oil burner service needed.
Very high smoke levels may indicate or even cause plugging up of the furnace or boiler, leading to improper oil burner operation, an unsafe system, and possibly other malfunctions, even a "puffback".
Setting an Oil Burner for Zero Smoke?
Technical note: on some modern oil fired heating systems the oil burner combustion air and oil pressure are adjusted to a standard of zero smoke rather than a trace of smoke.
To perform this adjustment correctly and to avoid over-firing or overheating the boiler, as well as to avoid an inefficient set-up that sends too much heat up the chimney, the heating service tech will first set the oil burner for just a trace of smoke (#1 in our photo at left), then s/he will slightly increase combustion air until the trace just vanishes to a zero smoke reading (#2 and #3 in our photo) with the test filter paper and smoke gun.
Watch out: Don't come at zero smoke from a position of too much combustion air or you won't know what you've got and you may be wasting fuel and overheating the equipment.
Thanks to Bob, a heating service technician at Bottini Oil, for this service tip.
Oil Burner Smoke Numnber Standards
While technicians and equipment suppliers commonly refer to a Bachrach smoke number or Bosch smoke number, these smoke measurements are also standardized in ISO 10054
Actually there are at least eleven different smoke level measurement standards. Homan (1985) reports on standardization among these.
The second common test performed by an oil heat technician evaluates the oil burner efficiency by measuring the carbon dioxide level or CO2 level in the oil burner exhaust.
Details of measuring the carbon dioxide level for oil burners, a second key measurement needed for proper setting of oil burner combustion air & operating temperature are now at OIL BURNER CO2 TEST
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. There 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.
Combustion Analyzer Recommendtions & Sources of Oil or Gas Burner Combustion Testing Kits include Oil Burner Smoke Level Measuring Devices
Bachrach Inc. provides the Fyrit ® Classic Oil Kit (shown in the case photos above) for testing oil or gas burners, as well as a number of other test instruments such as the Fyright® Insight® Plus (electronic), Fyrite Intech®, the ECA450, and the PCA 3 portable combustion analyzer. Website: http://www.bacharach-inc.com/combustion-test-kits.htm, Bacharach Sales/Service Center
621 Hunt Valley Circle
New Kensington, PA 15068-7074
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 Beckett Corporation, 38251 Center Ridge Rd.,
North Ridgeville, OH 44039 440-327-1060 Email: firstname.lastname@example.org supplies residential and commercial oil burners for boilers, furnaces, and water heaters - see www.beckettcorp.com/
 Thanks to Bottini Fuel service. Bottini Fuel is a residential and commercial heating oil distributor and oil heat service company in Wappingers Falls, NY and with offices in other New York locations. Bottini Fuel, 2785 W Main St, Wappingers Falls NY, 12590-1576 (845) 297-5580 more contact information for Bottini Fuel
 Audels Oil Burner Guide, Installation, Servicing, Repairing, Frank D. Graham, 1947 edition (obsolete, out of print). See Brumbaugh, James E. Audel HVAC Fundamentals, Volume 2: Heating or see various versions of this guide available in editions from 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
 Homan, H., "Conversion Factors among Smoke Measurements," SAE Technical Paper 850267, 1985, doi:10.4271/850267
Abstract from SAE:
A set of smoke measurement conversion equations are derived. The equations convert any of eleven smoke measurements to the other ten measurements. The eleven measurements are: Bosch, SAE, and ASTM (Bacharach) smoke numbers, Hartridge opacity, PHS opacity, Calesco model C107 opacity, extinction coefficient, transmittance, opacity, fraction of fuel carbons converted to smoke, and mass fraction of smoke in the exhaust gas. These eleven smoke measurement methods are described along with a general explanation of the consonance of smoke measurement methods, which allows one to derive equations for interconverting them. A FORTRAN program is listed which performs the conversions. The predictions of the program are shown to be within the scatter of published experimental data. However, published experimental data varies by as much as a factor of two. The conversion equations enable experimenters to choose a smoke measurement method which is sensitive to expected smoke concentrations. - retrieved 10/24/2013, original source http://papers.sae.org/850267/
Books & Articles on Building & Environmental Inspection, Testing, Diagnosis, & Repair
The Home Reference Book - the Encyclopedia of Homes, Carson, Dunlop & Associates Ltd., Toronto, Ontario, 2010, $69.00 U.S., is available from Carson Dunlop, and from the InspectAPedia bookstore. The 2010 edition of the Home Reference Book 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. InspectAPedia.com ®
sup> author/editor Daniel Friedman is a contributing author. Field inspection worksheets are included at the back of the volume.
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.
"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.)