It should be located as close as possible to the oil burner. Care should be taken to prevent air leakage in the oil suction line. Use continuous runs of copper tubing and use minimum number of joints and fittings. Always use flare fittings.
E.Adjustment of Electrodes Adjust ignition electrodes as specified in Figure 10.
F.Operate Burner Operate burner, adjust air setting for good flame by visual observation, and run for at least 10 minutes or until operation has stabilized.
G.Check Burner Pressure Bleed air from pump and nozzle piping. Check pump pressure and adjust to 100 psi, if necessary.
2.COMBUSTION ADJUSTMENT STEPS
H.Set Draft Check the draft reading over the fire with a draft gauge through a hole in the inspection door. The hole is above the flame level. Adjust the barometric draft regulator on the flue to give the over fire of
I.Check Smoke Readings After burner has been operating 5 or 10 minutes, make a smoke measurement in the flue, following the smoke tester instructions. 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 other factors. If this condition cannot be corrected, major renovation or even burner replacement may be necessary.
J.Develop Smoke - CO2 Curve Record
measurements of smoke and CO2 from the flue. Then establish the smoke - CO2 curve by taking readings over a range of air settings, as shown in Figure 8.
To do this, start with the air gate set at nearly
full open and then take smoke and CO2 readings at progressively lower air settings, as necessary to visualize the general shape of the
curve. (The CO2 readings will increase as the air setting is decreased, unless combustion is incomplete.) Do not set the air gate to give a smoke reading above No. 4 or No. 5. Plot the points on graph paper, as in Figure 8. Usually 3 or 4 readings are enough to establish the curve.
In adjusting each air setting, it is helpful to note the various positions of air gate at which measurements are made so that the final setting can be located quickly.
K.Adjust Air Setting Examine the smoke - CO2 plot and, keeping in mind the curve of Figure 6, 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 CO2 level 1/2 to 1 percent lower than the CO2 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. In such cases, the setting should be made near the minimum smoke, (using judgement).
Lock the air adjustment and repeat draft,
CO2 and smoke measurements to make sure the setting has not shifted.
3.COMBUSTION DIAGNOSIS
L.Check Performance A
If this cannot be reached, check the following:
1.Air leaks into the combustion chamber or heat exchanger can dilute the combustion
gases and prevent normal CO2 readings. Such leaks should be sealed with furnace cement or other
To check for dilution by leakage, measure
the CO2 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 compare this with the
CO2 measured in the flue. A difference of more than 1 percent CO2 between the flue and overfire reading usually indicates air entry through leaks that have not been properly sealed.
Seal between the probe and inspection door sample hole during test. The inspection door hole should be sealed when not being used to avoid leakage of air through it. (See Step H.)
2.If the CO2 level of 10% cannot be reached without exceeding No. 2 smoke, poor mixing of air and fuel is likely.
It may be necessary to replace the combustion head or try different settings.
Manual
