October 1975 E PA-600/2-75-069-a
GUIDELINES FOR RESIDENTIAL OIL-BURNER ADJUSTMENTS
Oil-Burner Adjustment Procedures to Minimize Air Pollution
and to Achieve Efficient Use of Fue!
Guidelines intended for use
— by skilled service technicians in
adjustment of residential oil burners.
— as a training guide fot advanced
burner service courses
— as a supplement to manufacturers'
service instructions.
4?
a
•*
EPA, Office of Research and Development
Industrial Environmental Research Laboratory
Research Triangle Park, NC 27711
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-i-
TABLE OF CONTENTS
Page
PURPOSE OF THESE GUIDELINES 1
RECOMMENDED ADJUSTMENT PROCEDURES FOR RESIDENTIAL OIL BURNERS 3
Preparation Steps 3
Combustion Adjustment Steps 5
Combustion Diagnosis . . ....... 7
Final Checks 9
APPENDIX BACKGROUND INFORMATION
A. Pollutants of Main Concern A-l
B. Field-Type Instruments and Significance of Measurements B-l
C. Typical Emission Characteristics of Residential Oil Burners C-l
D. Example Short-Form Adjustment Procedure D-l /"
E. References E-l
ACKNOWLEDGEMENT
These Guidelines were prepared by David W. Locklin and Richard E. Barrett
of Battelle-Columbus Laboratories under EPA Contract No. 68-02-0251, with participa-
tion by representatives of the heating industry and of the Environmental Protection
Agency, including Robert E. Hall, Project Officer. Special acknowledgement is due
the reviewers from industry, including committee members from
- Air Pollution Control Association
- American Petroleum Institute
- National Association of Oil Heat Service Managers
- National Oil Fuel Institute.
This report has been reviewed by the Environmental Protection Agency and is
approved for publication. Any mention of trade names or commercial products does
.not constitute endorsement by the Government or its contractors. This report may
be reproduced or reprinted if reference is made to the U. S. Environmental
Protection Agency and to report number EPA-600/2-75-069-a.
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GUIDELINES FOR
RESIDENTIAL OIL-BURNER ADJUSTMENTS
In the past, the most important reason for adjustment of oil burners has been to
ensure reliable automatic operation. A second important reason has been to provide efficient
fuel utilization. Common good practice of adjusting a burner for minimum air setting, con-
sistent with acceptable smoke levels, is an effective way of meeting both objectives.
Recently, a third objective has been added, that of minimizing air pollution. It
is important to recognize that any burner adjustments for this purpose must also meet the
former requirements. Fortunately, adjustments for low air-pollutant emissions can still meet
the objectives of reliable and efficient operation.
PURPOSE OF THESE GUIDELINES
These Guidelines have been prepared for use by service managers for service
training and by skilled service technicians in their oil burner service work. By following
these Guidelines, the skilled oil-burner service technician will be able to adjust residential
oil burners to minimize air pollution and get the most useful heat from the fuel fired.
Adjustment procedures recommended here apply to automatic oil burners used for heating
of homes, ranging from single-family dwellings to three-family dwellings. They apply generally
to a capacity range up to approximately 400,000 Btu/hr output. Apartment buildings are covered
in separate Guidelines being issued by EPA for commercial oil-fired boilers.
These Guidelines should be used as a supplement to the equipment manufacturers'
installation and service instructions, plus the handbooks and manuals on good service practice
developed by oil-heating industry specialists.
Burner service organizations may wish to develop their own short-
form recommendations that tie in with overall company policy, service
training doctrine, abilities of the service technicians, and local
regulations. Included at the back of these Guidelines in Appendix D
is an example of such a short form prepared by the National Associa-
tion of Oil Heat Service Managers.
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Chimney.
Stack ^
Draft regulator^
Location for stack
sampling hole, '/4 diam •
Furnace or.
boiler
Oil burner
Note A
NoteB
Morizonial Stack Connection
Stack t
Ci
XV
ireeching par"
.ocationfor stack
sampling hole
Note B Note A
T 1
N^AT^
—
~
Vertical Stack Connection
Figure 1. Desirable Location for 1/4" Stack Sampling Hole
for Typical Stack Connections
A. Locate hole ^t least one stack diameter on
the furnace or boiler side of the draft control.
B. Ideally, hole should be at least 2 stack
diameters from breeching or elbow.
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RECOMMENDED ADJUSTMENT PROCEDURES
FOR RESIDENTIAL OIL BURNERS
These procedures are intended for adjustment of gun-type oil burners for residential
heating systems and are supplemental to manufacturers' installation instructions or other
service handbooks.(^»2>3)
The following steps are emphasized from the viewpoint of minimizing air-pollutant
emissions:
PREPARATION STEPS
1. CLEAN &
SEAL
Make sure the burner blast tube, fan housing, and blower wheel are
clean of dirt and lint. Seal any air leaks into the combustion
chamber, especially joints between sections of cast-iron boilers
(and around fire door).
2. NOZZLE
3.
SAMPLING
HOLE
Annual replacement of nozzle is recommended. The nozzle size
should match the design load. DO NOT OVERSIZE. Short cycles
and low percent "on" time result in higher overall pollutant
emissions and lower thermal efficiency. An in-line oil filter
will reduce service problems due to nozzle clogging.
Select the nozzle and spray pattern to match the air pattern
produced by the mixing head and, for matched units, follow the
manufacturer's instructions.
Drill a 1/4" hole in the stack or flue duct between the unit and
the barometric draft regulator (if -not already drilled by the
installer). This is for taking smoke and C02 samples. It can
also be used to insert a stack thermometer.
[See Figure 1.] If space permits, the hole should be located in
a straight section of the stack, at least 2 stack diameters from
the unit breeching and at least one diameter from the unit side
of the draft regulator.
4. ADJUST Adjust ignition electrodes to assure prompt ignition.
ELECTRODES
5. OPERATE Operate burner, adjust air setting for good flame by visual
BURNER observation, and run for at least 10 minutes or until operation
has stabilized.
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Z
0)
JC
o
E
o
o
L.
O
JC.
o
o
CD
High air settings
Low air settings
Smoke-C02 Curve
Normal adjustment range
Tolerance to "knee"
Test points
8 10
Percent COa in Flue Gas
12
Figure 2. Typical Smoke-CC^ Characteristic for a Residential Oil
Burner — With Recommended Air Adjustment
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6. CHECK
BURNER
Bleed air from pump and nozzle piping. Check pump pressure and
adjust to 100 psi, if necessary (or to manufacturer's recommen-
dation) .
COMBUSTION ADJUSTMENT STEPS
7. SET
DRAFT
Check the draft reading over the fire with a draft gage through
a 1/4" hole drilled in the fire door or inspection door. [This
hole should be in the inspection door for oil-fired-matched units,
or in the fire door for conversion installations. If possible,
the hole should be above the flame level.]
Adjust the barometric draft regulator on the stack to give the
overfire draft recommended by the manufacturer. If no such
recommendations are available, set overfire draft to assure a
negative pressure within the combustion chamber (usually 0.02
inches water column).
With some equipment, it will not be possible to take draft readings
over the fire. In this case, adjust the draft regulator to give a
stack draft reading between 0.04 and 0.06 inches water column (taken
at the stack sampling hole.)
Seal draft or sampling hole in inspection or fire door after these
tests have been made, using a plug, bolt, or high-temperature seal-
ant. (It is not necessary to seal the stack sampling hole).
8.
CHECK
SMOKE
After burner has been operating 5 or 10 minutes, make a smoke
(2)
measurement in the stack, following the smoke tester instructions.
Pump the tester slowly for 10 full strokes. On pull stroke, use a
steady motion such that a full stroke is obtained in 3 or 4 seconds.
Allow a 2-second pause between pump strokes to insure a full sample.
Oily or yellow smoke spots on the filter paper are usually a sign
of unburned fuel, indicating very poor combustion (and likely high
emissions of carbon monoxide and unburned hydrocarbons). This
condition can sometimes be caused by too much air, or by factors
mentioned in the diagnosis section. If this condition cannot be
corrected, major renovation or even burner replacement may be
necessary.
9. SMOKE-C02
CURVE
Record measurements of smoke and C02 from the stack. (When making
C0« readings, follow the instrument manufacturer's instructions.)
Then establish the smoke-C02 curve by taking readings over a range
of air settings, as shown in Figure 2.
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13
tt) J
"O
V)
c. 4
o
2
o
jc
o -i
o 3
m
8 9 10 II 12
Percent COg in Flue Gas
13 14
Figure 3. Sample Graph Paper for Service Technician's
Plot of Smoke-CO2 Characteristic
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To do this, start with the air gate set at nearly full open and
then take smoke and CCL readings at progressively lower air
settings, as necessary to visualize the general shape of the
curve. (The C(>2 readings will increase as the air setting is
decreased, unless combustion is incomplete.) Do not set air
gate to give smoke reading above No. 4 or No. 5. Plot the points
on graph paper, as in Figure 3. Usually 3 or 4 readings are
enough to establish the curve.
In adjusting each air setting, it is helpful to mark the various
positions of the air gate at which measurements are made so that
the final setting can be located quickly.
10. SET Examine the smoke-C09 plot and, keeping in mind the curve of
AIR
Figure 2, note the location of the "knee" where the smoke number
begins to rise sharply. Noting the air gate position marks,
adjust the air setting to a CO- level 1/2 to 1 percent lower
than the CC>2 level at the "knee". (This provides a tolerance
against possible shifts in the setting over a period of time.)
Do not increase the air setting any more than necessary on the
lower portion of the curve below the "knee".
(The characteristic curve for some burners may not yield a
distinct "knee" in the curve. Burner A in Figure 5 of the
Appendix has no distinct "knee". In such cases, the setting
should be made near the minimum smoke, (using judgment).
Lock the air adjustment and repeat draft, 002, and smoke measure-
ments to make sure the setting has not shifted.
COMBUSTION DIAGNOSIS
11. CHECK A well-matched and well-tuned burner should be capable of opera-
tion with smoke not greater than No . 2 and at a C02 level not
less than listed in Table 1. If this cannot be reached, check
the following:
A. Air leaks into the combustion chamber or heat exchanger
can dilute the combustion gases and prevent normal C02
readings. Such leaks should be sealed with furnace
cement or other high-temperature sealant.
To check for dilution by leakage, measure the C02 at as
high a point as possible over the fire, using a stainless
steel tube inserted through the fire door sample hole (as
described earlier for overfire draft measurements), and
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TABLE 1. TYPICAL AIR ADJUSTMENTS FOR DIFFERENT
TYPES OF RESIDENTIAL BURNERS
OIL-BURNER TYPE
Typical CO.
in Flue Gas
When Tuned*
HIGH-PRESSURE GUN-TYPE BURNERS
• Old-Style Gun Burners 8 %
- No internal air-handling parts other
than an end cone and stabilizer
• Newer-Style Gun Burners 9 %
- special internal air-handling parts
• Flame-Retention Gun Burners 10 7°
- flame-retention heads
OTHER TYPES OF BURNERS
• Atomizing Rotary Burners
- ABC, Hayward, etc.
• Rotary Wall-Flame Burners
- Titnken, Fluid-Heat, Torridheet, etc.
• Miscellaneous Low-Pressure Burners
8 %
12
**
* Based on acceptable Bacharach smoke— generally No. 1 or trace, but
not exceeding No. 2.
Caution should be used in leaving burners with CO level higher
than 13%.
** See manufacturer's instructions.
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compare this with the C02 measured in the stack.
A difference of more than 1 percent C0£ between
the stack and overfire readings usually indicates
air entry through leaks that have not been properly
sealed.
Seal between the probe and fire door sample hole
during test (for example, with asbestos rope). The
fire door hole should be sealed when not being used
to avoid leakage of air through it. [See Step 7.]
B. If the CC>2 level in Table 1 still cannot be reached
without exceeding No. 2 smoke, poor mixing of air and
fuel is likely.
This could be caused by a. combustion head (blast tube
nose piece) with too large a throat for good mixing,
or an improper match between air pattern and nozzle
spray pattern. Frequently, replacement of the nozzle
with one having different spray angle and pattern will
improve performance.
It may be necessary to rsplace the combustion head or
try different settings if the burner is equipped with
an adjustable head or mixing devices. Modern flame-
retention heads can be adapted to fit most blast tubes.
C. The combustion chamber must be matched in size and shape
to the nozzle spray and the burner air pattern. Oversize
chambers do not insure adequate mixing. Undersize chambers
may allow flame impingement on the chamber walls or heat
exchanger.
FINAL CHECKS
12. STACK Operating the unit at excessive firing rate will generate more heat
TEMPERATURE
than the heat exchanger can utilize and result in unnecessary heat
loss up the stack. Other causes of excessive heat loss are badly
sooted heat-exchanger surfaces and excessive draft. The tempera-
ture of the flue gas provides an indication of these heat losses.
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10
13. IGNITION
Measure stack temperature after at least 5 minutes of operation.
Determine the net stack temperature by subtracting the room air
temperature from the thermometer reading. Excessive stack loss
is indicated if the net stack temperature during steady opera-
tion exceeds 400° to 600° F for matched-package units, or 600°
to 700° F for conversion burners.
Check operation over repeated cycles to insure prompt ignition on
starting.
14. PUMP
CUTOFF
Slow pump cutoff at the end of a firing cycle can cause smoke
and other pollutant emissions. Check for prompt pump cutoff
by observing flame or by testing smoke at shutdown. If poor
cutoff is observed, make sure air is purged from the pump and
nozzle line. Air trapped in the pump or nozzle line will expand
when heated, thus causing oil to drip into the combustion chamber
after shutdown. If poor cutoff persists, repair or replace pump.
(A solenoid valve in the nozzle line should insure prompt cutoff.
If it does not, replace or repair solenoid.)
1-5. CONTROLS Check settings of all operating and limit controls before leaving
the installation.
16. ANNUAL
CLEANUP
An overall burner checkup and cleanup is recommended annually.
Experienced service technicians will observe that these procedures are essentially
the same as they have followed in normal good practice. The added aspect of specific visuali-
zation of the smoke-C02 curve helps in adjusting for good performance and in diagnosing prob-
lems.
Adjustment of residential oil burners by these procedures will minimize emissions
and provide efficient fuel utilization.
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A-l
APPENDIX: BACKGROUND INFORMATION
Information on the air-pollutant effects of different burner adjustment procedures
have been developed in recent field and laboratory investigations^'^' »'', including those
conducted cooperatively by the U.S. Environmental Protection Agency and the American Petroleum
Institute.' »'' The findings of these investigations, combined with good field practice, are
the basis for the Guidelines.
This Appendix contains additional background information as follows:
A. POLLUTANTS OF MAIN CONCERN
B. . FIELD-TYPE INSTRUMENTS AND SIGNIFICANCE
OF MEASUREMENTS
C. TYPICAL EMISSION CHARACTERISTICS OF
RESIDENTIAL OIL BURNERS
D. EXAMPLE SHORT-FORM ADJUSTMENT PROCEDURE
E. REFERENCES
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A-2
APPENDIX: BACKGROUND INFORMATION
A. POLLUTANTS OF MAIN CONCERN
Pollutants and Their Measurement
The air pollutants of main concern for the purposes of these Guidelines can be
divided into three broad classes, depending upon how much the serviceman can control them
by his adjustments. These classes are:
Class 1+ Pollutants that may result from incomplete combustion and are
generally strongly affected by burner adjustment procedures:
• Smoke and particulate*
• Carbon monoxide, CO
• Hydrocarbons, HC
Class 2. Pollutants only partially affected by burner adjustment procedures
(and not recommended as adjustment criteria).
Nitrogen oxides: NO and N©2 (usually
considered together and identified as
NOX)
Class 3. Pollutants not affected by burner adjustment procedures but
depending only on sulfur content of the fuel.
• Sulfur oxides (S02 and S03)
The following comments describe each of the Class 1 pollutants from the viewpoints
of definition, hazards associated with the pollutant, how it is detected or measured, and
how emissions of the pollutant are affected by service adjustments. (The Class 2 and Class 3
pollutants are not discussed further here, because the serviceman has little or no control
over them by adjustment.)
Smoke and Particulate
Smoke consists mainly of tiny unburned particles of carbon. Smoke has long been an
important factor in the adjustment of oil-burning equipment to avoid fouling of heat- transfer
* Particulate that is formed from the ash content of the fuel oil is not affected by burner
adjustment. However, the carbon or soot portion of particulate, usually the larger portion,
can be strongly affected by burner adjustments.
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A-3
passages with soot, to achieve efficient fuel utilization, and to avoid general complaints
resulting from visible smoke and fallout of large particles.
Over the past 25 years, the development and the use of the filter-paper method of
smoke measurement (as used, for example, in the Bacharach Smoke Tester) has allowed a much
/•I f\ Q\
more sensitive measurement than by visual means such as the Ringlemann Scale. *• > » > The
method is now an accepted ASTM standard^ and is widely used in the oil-burning industry to
assist in field adjustments.
Particulate is the usual scientific term applied to air-pollution measurements in
terms of weight of solid and liquid materials being emitted to the atmosphere. "Particulate"
is defined by the U.S. Environmental Protection Agency as "any finely divided solid or liquid
material, other than uncombined water, as measured by EPA Method 5". ' '
Particulate is composed of unburned fuel, carbon or soot, ash constituents in the
fuel*, and noncombustible-airborne dust that enters with the combustion air.
Coarse particles do not carry far in the atmosphere and usually fall out near the
stack. Fine particles, the predominent portion of particulate from oil burning, can remain
in the atmosphere for long periods and can obscure long-range visibility. In addition, parti-
culate can deposit on lung tissues and, therefore, result in respiratory impairment if present
in high concentrations. These are the reasons particulate is of concern to air-pollution
control.
Smoke and COo measurements provide a simple and relatively reliable means to avoid
high emissions of pollutants (including particulates associated with incomplete combustion).
The service technician can exert considerable control over particulates by ensuring that the
fuel pump and safety shut-off valve has good cutoff characteristics and by the burner adjust-
ments he chooses.
For steady operation, smoke measurements by the filter-paper method are the most
practical method to warn of high particulate levels, as discussed in Appendix C, ' Parti-
culate measurements by EPA standard measuring techniques require special equipment and
techniques, plus long sampling periods — which are not practical for most residential burner
adjustments.
* Ash is extremely low for No. 2 heating oil, usually below 0.005 percent.
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A-4
Carbon Monoxide. CO
CO is a toxic gas formed by incomplete combustion. When oil-burning equipment 'is in
good adjustment, the CO level is very low. But with improper combustion, CO can reach
levels which can be dangerous if gases should leak into living spaces. When the low levels of
CO that are emitted by properly operating residential-oil heating equipment are diluted in the
atmosphere, CO is not considered dangerous and is depleted with time in the atmosphere.
For field adjustment of most conventional oil-fired residential equipment by methods
suggested in these Guidelines, it is seldom necessary to measure CO. Smoke measurement can be
used as a detector of poor combustion that could lead to the onset of CO at low excess-air
levels (high C02 levels). However, if the serviceman increases the air setting too far, CO
levels occasionally will increase rapidly without smoke; therefore, the air setting should not
be increased beyond that necessary to obtain a satisfactory smoke reading below the "knee" on
Figure 2.
Hydrocarbons, HC
Emissions of hydrocarbons from oil-burning equipment occur when combustion is in-
complete; they can consist of unburned or partially burned fuel vapors.
Although hydrocarbons are generally not toxic to the same extent as CO [or NOX],
they can be accompanied by unpleasant odors and can contribute to photochemical smog in the
atmosphere. Essentially, no hydrocarbons are emitted when equipment is properly adjusted.
If large amounts of unburned oil vapor should be emitted from an improperly operating
installation, this can be detected as oily or yellow deposits on the filter paper during smoke
measurements. At lower levels of hydrocarbon emissions, the emissions generally follow trends
of smoke or CO emissions and, hence, these measurements are usually a good indicator of whether
hydrocarbon emissions are high or low (except at extremely high air settings where smoke
readings may fail to indicate a rise in hydrocarbons).
For routine adjustment of residential oil burners, it is not necessary to measure
hydrocarbons by chemical or analytical means. If the service technician detects hydrocarbon
odors (unburned oil vapor) near the burner or near the barometric draft control, he should
check for flame impingement, improper nozzle size, improper adjustment of the combustion head,
or improper pump cutoff. [See page 10].
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B-l
B. FIELD-TYPE INSTRUMENTS AND SIGNIFICANCE
OF MEASUREMENTS
For the adjustment procedures outlined in these Guidelines, it is assumed that the
service technici*
kit includes the following:
oil-burner service technician is accustomed to using field-type instruments. A typical
C02 tester for stack-gas analysis
- a simple wet-chemical absorbent-type analyzer
(for example, Fyrite or Orsat apparatus)
- C02 readings are used to provide an indication of the
combustion air setting.
Smoke tester and shade scale
- hand-pump version of the ASTM filter-paper method for
smoke determination.(9)
- includes a shade scale for evaluating smoke spots from
0 to 9 (Bacharach or ASTM Scale).
(This is not a Ringlemann scale. Smoke levels below
about 5 on the Bacharach scale are generally not
visible from a residential-size stack against the sky.)
• Thermometer for measuring stack temperature
- usually a dial type, but liquid thermometers are more
accurate.
• Draft Gauge
- for draft measurements in the stack or overfire.
• CO detector for dual-fuel commercial boilers
- usually color-sensitive chemical in tubes.
Instruments which combine several of these readings in one device are being introduced on
the market and offer convenience in use.
The Significance of C02 Measurements
C02 readings are used to identify how much combustion air is being supplied to the
burner, compared to the theoretical amount required for combustion. It is seldom possible to
burn a fuel completely and cleanly unless air in excess of the theoretical amount is provided.
The following values will illustrate the relationship between excess air supplied for combus-
tion and the C02 concentration in the flue gas for residential oil burners firing No. 2 heating
oil.
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B-2
Air /Fuel
Mixture
Settings
Excess-Air Supply
(percent above
theoretical)
co2
in flue gas,
Comments on Combustion
Performance (assuming
satisfactory smoke levels)
Theoretical or
"Chemically Correct"
15
"Stoichiometric mixture"
(cannot be achieved for
reliable operation in-
practice)
Typical for
Residential Equipment
35 T.
70 %
150 %
11 1
9%
6 I
Excellent performance
Average performance
Poor performance
The overall efficiency of fuel utilization is lowest at the low levels of CCL (high excess air),
because the products of comb'ustion are diluted by the excess combustion air and carry more heat
up the stack.
The Significance of Smoke Measurements
The filter-paper method of smoke measurement is useful in assessing the sooting
(2)
characteristics of a combustion process. In this method, a measured sample is drawn through
(9)
a filter paper and smoke spots are compared to a standard shade scale (commonly known in the
oil-heating trade as the "Bacharach shade scale".) The method offers a practical and sensitive
(12)
means of judging the combustion of fuel oils and can be used as a rough indicator of parti-
culate emissions during steady-state operation. [See comments below on smoke scale.]
Bacharach Comments on Combustion Performance
Smoke (assuming satisfactory CC>2 level)
Comments on Sooting of
Heating Surfaces Anticipated
(2)
No. 0
No. 1
No. 2
No. 3
No. 4
No. 5
or higher
Excellent
Excellent
Good
Average for untuned burners
Poor
Very Poor
None
Extremely light if at all
Slight sooting which will not
increase stack temperature
appreciably
May be some sooting but will
rarely require cleaning more
than once a year
Borderline condition. Some
units will require cleaning
more than once a year
Potential for rapid and heavy
soot buildup
For reliable smoke readings, it is important that the manufacturer's instructions
with the smoke tester be followed carefully. For example, the sample should be pumped slowly
from the stack with full strokes, with several seconds pause at the end of the pullstroke to
(2)
allow a full sample.
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B-3
The Significance of Stack Temperature:
Its Effect on Efficiency
Stack temperature is significant in determining the effectiveness of fuel utilization
because it is an indicator of the amount of heat lost up the stack.
Stack temperature can be considered abnormally high if the net stack temperature
(stack temperature minus room air temperature) should exceed:
400° - 600° F for matched package units, or
600° - 700° F for conversion units.
A high stack temperature may indicate one of the following conditions:
1. Excessive firing rate for furnace or boiler size
2. Dirty or soot-covered heating surfaces
3. Need for effective baffling of flue passes
4. Improper adjustment of the draft regulator,
usually excessive draft through the unit.
These points should be checked and remedied if stack temperature is abnormally high.
"Overall thermal efficiency" is defined as the proportion of the heat energy in fuel
that is actually available for heating the dwelling during continuous burner operation. Two
factors can be used to determine the heat lost up the stack and, therefore, the overall thermal
efficiency. These factors are:
• Net stack temperature
(actual stack temperature reading minus the loom temperature)
• Percent CC^ in the flue gases.
Figure 4 shows the combined effects of these two factors on overall thermal efficiency. '
This figure is based on continuous operation and use of No. 2 heating oil. It also assumes
that heat from the unit jacket is available for heating some portion of the dwelling; otherwise,
the overall thermal efficiency will be reduced by this jacket loss (usually only a few percent).
The overall thermal efficiency is sometimes referred to as "combustion efficiency";
however, it is also dependent on the effectiveness of the heat transfer surfaces in the boiler
or furnace.
Seasonal thermal efficiency is less than the continuous thermal efficiency in
Figure 4, because of lower efficiency during cyclic operation (e.g., additional losses up the
stack from the unit during off-periods). Seasonal efficiency will be highest for units that:
1. Have high overall thermal efficiency during continuous operation
2. Have good starting and shutdown characteristics
3. Have firing rates matched to the design load.
(Overfiring results in excessively long shut-down periods.)
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B-4
90
85
80
75
70
65
60
55
50
600
800 r,
10
I I
12
13
14
15
Percent CO^. in Flue Gas
Figure 4. Effect of Stack Temperature and CCU on Overall Thermal
Efficiency-
Basis: • Continuous operation
• No. 2 heating oil
•• Heat from unit jacket contributes
to heating dwelling, so only loss
is stack heat loss.
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C-l
C. TYPICAL EMISSION CHARACTERISTICS OF
RESIDENTIAL OIL BURNERS
Figure 5 illustrates the performance characteristics of three different but typical
gun-type oil burners. This figure shows the relationship between smoke and carbon dioxide
(C02), as measured with field-type measurements.
The three burners represent different and unique characteristics. Burner C has
superior operating characteristics, in that the combustion air can be set to a higher CC>2 level
and still maintain a low smoke level. Other burners could have still other characteristics,
but these are typical. It is possible to shift from one characteristic curve to another in
"tuning", such as by a nozzle change or by burner cleaning.
Low CO. levels indicate excess combustion air; high C^ levels indicate an approach
to the theoretical air requirement for combustion. (See Appendix B.) It is important that the
service technician visualize this curve as he changes the air setting and makes measurements of
C09 and smoke. During steady operation, particulate emissions would be expected to follow the
(7)
same general trends as smoke.
Particulate matter is also formed during burner starting and shutdown. Poor starting
performance by ignition delay or resulting from shifts in nozzle delivery rates can result in
high levels of smoke and particulate over a period of cyclic operation.('' Poor pump cutoff
can also result in increased smoke and particulate generation at the end of a cycle.
I I I I I I
Percent C02 in Flue Gas
Figure 5. Different Burners have different
Smoke-CO2 Curves
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C-2
t
HC
High air settings
Low air settings
I
CO
t
Smoke
Normal
adjustment range
Increasing C02 in Flue Gas
Figure 6. Typical Relationships of Carbon Monoxide and
Hydrocarbon Emissions to Smoke when
Changing the CC^ Setting for Residential Oil
Burners
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C-3
Figure 6 illustrates typical trends of CO and HC in relation to smoke as the C02
setting is varied. Note the following trends:
1. As C0_ is increased (by closing the combustion air setting)
a. Smoke rises sharply beyond the normal operating
C02 range.
b. CO and HC begin to rise. Here smoke has served
as an indicator to forewarn of this increase.
2. As C02 is decreased (by opening the combustion air setting)
a. CO starts to rise sharply below the normal operating
CO range.
b. HC begins to rise after CO rises.
c. Smoke usually remains lowj so that smoke is no longer
a good indicator of high CO and HC emissions.
Not all burners will perform in this way. In some, the "normal operating" range will be wider,
in others narrower, and in some p<
picture of general relationships.
(4-7)
in others narrower, and in some poor units nonexistent. However, Figure 6 provides a
The service technician should visualize the interaction of the various pollutants to
develop an appreciation for the fact that the smoke-CO, characteristic is basic to setting an
oil burner for minimum emissions by use of field-type instruments. Note that adjustments made
with only a smoke limitation in mind could result in high CO and HC at the low C02 end of the
adjustment range (high excess air). This can be avoided in most cases by adjusting the C02
setting closer to, but still below the "knee" of the smoke-CO^ curve.
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D-l
D. SHORT-FORM ADJUSTMENT PROCEDURE
Burner service organizations may wish to develop short-form recommendations that tie
in with overall Company policy, service training doctrine, experience of service technicians and
local regulations. The following is an example of such a short form prepared by the National
Association of Oil Heat Service Managers.Q**J
STEP #1. Service & Clean Burner
Follow Company procedure to complete the cleaning and servicing.
Operate burner for ten minutes while tools are gathered and area
cleaned.
STEP #2. Check Draft
Set draft regulator, if necessary. If no manufacturer's recom-
mendations are available, a minus draft over the fire of 0.02
to 0.04 inches of water is acceptable. Draft readings in the
breeching will be higher depending on the flue passages of the
boiler. The more restricted and lengthy the flue» the higher
the draft necessary to obtain the accepted over-fire conditions.
STEP #3. Smoke Test
Follow the instructions of the manufacturer of the smoke tester
and take a smoke test. Adjust the air to obtain a preliminary
reading of about No. 3 spot. Then readjust the air to obtain
the lowest possible reading, but do not open the air adjustment
more than absolutely necessary to obtain a trace or No. 0 spot.
STEP #4. C02 Test
Follow the instruction of the manufacturer of the C02 gas analyzer,
take a C02 test. The following results should be obtained:
a. Old"Style Gun Burners (burners with no special air-handling
parts other than an end cone and stabilizer). A C02 reading
of 77o to 97o should be obtained. If the reading is less,
reduce the air until a satisfactory C02 reading is reached.
In no case should the air be reduced to a point where the
smoke reading exceeds a No. 3 spot. If a No. 2 smoke or less
cannot be obtained with the above C02 reading, proceed as
directed by the Company.
b. Newer Style Gun Burners (burners with special air-handling
parts.) Follow the same procedures as above except that C02
readings should be in the 97<> and 11% range.
c. Flame-Retention Gun Burners. Follow the same procedures as
above except the C02 readings should be in the 107, to 127,,
range.
d. Rotary Burners (Hayward, ABC, etc.) Follow the same procedure
as outlined under old-style gun burners.
e. Rotary Wall-Flame Burners (Timken, Fluid-Heat, Torridheet, etc.)
Follow the procedures as outlined above, with the exception that
the appearance of the flame is important and the draft settings
critical. Higher C02 readings are obtainable, as much as 13.57<>
is common. The best procedures for adjusting these burners are
to be found in the manufacturer's service manuals.
f. Miscellaneous Low Pressure Burners. As mentioned in the previous
paragraph, in most cases the manufacturer's service manual contains
the best adjustment procedures. In the absence of such specific
instructions, follow the procedure as outlined under Steps 4a, b,
or c.
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E-l
E. REFERENCES
1. "Evaluate Burner Performance", Fueloil and Oil Heat, October 1973, pp. 36.
2. "Oil Burner Combustion Testing", Bulletin 4011. Available from Bacharach Instrument
Company, 625 Alpha Drive, Pittsburgh, Pa. 15238.
3. Domestic and Commercial Oil Burners—Installation and Servicing, C. H. Burkardt. 3rd. Ed.
McGraw-Hill Book Company, New York, 1969.
4. "A Study of Air Pollutant Emissions from Residential Heating Systems", R. E.. Hall, J. H.
Wasser, and E. E. Berkau. Environmental Protection Agency, Report No. EPA-650/2-74-003
(January 1974). NTIS* Report PB-229,667.
5. "A Field Investigation of Emissions from Fuel Oil Combustion for Space Heating", A. Levy,
S. E. Miller, R. E. Barrett, E. J. Schulz, R. H. Melvin, W. H. Axtman, and D. W. Locklin.
A report by Battelle-Columbus Laboratories to the American Petroleum Institute. API
Publication No. 4099 (November 1, 1971).**
6. "Field Investigation of Emissions from Combustion Equipment for Space Heating", R. E.
Barrett, S. E. Miller, and D. W. Locklin. A report by Battelle-Columbus Laboratories to
the U.S. Environmental Protection Agency and the American Petroleum Institute. EPA Report
R2-73-084a (June 1973). API Publication No. 4180.** NTIS* Report PB-223,148.
7. "Investigation of Particulate Emissions from Oil-Fired Residential Heating Units", R. E.
Barrett, D. W. Locklin, and S. E. Miller. A report by Battelle-Columbus Laboratories to
the U.S. Environmental Protection Agency and to the American Petroleum Institute. EPA
Report No. EPA-650/2-74-026 (March 1974). NTIS* Report PB-273,355.
8. "Smoke Measurement in a Fuel Oil Test Unit", D. W. Locklin and G. B. Parmelee. ASHVE
Research Laboratory, ASHVE Transactions. 57. 1951, pp. 129.
9. "Standard Method of Test for Smoke Density in the Flue Gases from Distillate Fuels", ASTM
02156-65(70). ASTM Standards for Petroleum Products (Part 17).
10. "Standards of Performance for New Stationary Sources", Federal Register. 37. No. 55, Part I,
March 21, 1972, pp. 5767.
11. "Chemical Composition of Particulate Air Pollutants from Fossil-Fuel Combustion Sources",
L. H. Hillenbrand, R. B. Engdahl, and R. E. Barrett. A report by Battelle-Columbus
Laboratories to the U.S. Environmental Protection Agency on EPA Contract EHSD 71-29
(March 1, 1973). NTIS* Report PB-219,009.
12. "Standard Method of Test for Effect of Air Supply on Smoke Density in Burning Distillate
Fuels", ASTM D2157. ASTM Standards for Petroleum Products (Part 17).
13. "Combustion Efficiencies as Related to Performance of Domestic Heating Plants", A. P. Kratz,
S. Konzo, and D. W. Thomson. University of Illinois, Bulletin No. 42, Engineering Experi-
ment Station Circular Series 44 (June 9, 1942).
14. "Short-Form Adjustment Procedure", prepared by Ad Hoc Committee of Oil Heat Service Managers
for Review of Guidelines for Burner Servicemen. Rodney M. Terminello, Chairman
(March 11, 1975).
* Available from National Technical Information Service, Springfield, Va. 22151.
** Available from American Petroleum Institute, 1801 K Street, N.W., Washington, D.C. 20006.
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E-2
TECHNICAL REPORT DATA
(Please read Instructions on the reverse before completing)
1. REPORT NO.
EPA-600/2-75-069-a
NTIS No. PB 248-292/AS*
3. RECIPIENT'S ACCESSION NO.
4. TITLE ANDSUBTITLE
Guidelines for Residential Oil-Burner Adjustments
5. REPORT DATE
October 1975
6. PERFORMING ORGANIZATION CODE
7. AUTHOR(S)
David W. Locklin and Richard E. Barrett
8. PERFORMING ORGANIZATION REPORT NO.
9. PERFORMING OR3ANIZATION NAME AND ADDRESS
Battelle-Columbus Laboratories
505 King Avenue
Columbus, Ohio 43201
10. PROGRAM ELEMENT NO.
1AB014; ROAP 21ADG-AM
11. CONTRACT/GRANT NO.
68-02-0251
12. SPONSORING AGENCY NAME AND ADDRESS
EPA, Office of Research and Development
Industrial Environmental Research Laboratory
Research Triangle Park, NC 27711
13. TYPE OF REPORT AND PERIOD COVERED
Guidelines
14. SPONSORING AGENCY CODE
5. SUPPLEMENTARY NOTES T£RL-RTP project officer is R.E.Hall, Mail Drop 65, 919/549-
8411, Ext 2477. Report is available from National Technical Information Service. (*)
6 ABSTRACT These guidelines contain recommended procedures for adjusting residential
oil burners to minimize air pollution and for efficient fuel use. They are intended
for use by skilled service technicians in adjusting burners, and as an aid to service
managers engaged in training service technicians. In addition to recommended steps
for burner adjustment, the guidelines also include appendixes of background material
on pollutants of main concern, field-type instruments and significance of measure-
ments , and emission characteristics of residential oil burners.
KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
Air Pollution
Space Heating
ombustion
Nitrogen Oxides
Nitrogen Oxide (NO) Heating
Sfitro gen Dioxide Burners
"moke Boilers
Carbon Monoxide
Hydrocarbons
Fuel Oil
Residential Buildings
b. IDENTIFIERS/OPEN ENDED TERMS C. COSATI Field/Croup
Air Pollution Control
Stationary Sources
Particulate
Emission Factors
Distillate Fuel Oil
No. 2 Oil
13B
13A
2 IB
07B
07C
2 ID
13M
. DISTRIBUTION STATEMENT
Unlimited
19. SECURITY CLASS (ThisReport)
Unclassified
21. NO. OF PAGES
25
20. SECURITY CLASS (This page)
Unclassified
22. PRICE
EPA Form 222U-1 (9-73)
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