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NORA Oilheat Technicians Manual

Chapter 7—Combustion 7-29 smoke tester. Place a finger over the end of sample tube and try to pull the plunger handle out and then release. The handle should return by itself to approximately the original position. If it does not, the hose, paper holder, and plunger should be checked for leaks. If leakage is indicated, the hose in the sampling line may need replacement. Leakage may also occur if the surfaces of the filter paper holder are damaged. These areas (on the nylon inserts) should be inspected. The plunger can be removed for inspection if leakage is occurring across the plunger. B. A clean piece of filter paper should be clamped in the smoke tester and a 10 stroke sample of fresh air taken after very dark smoke readings have been observed. If the air sample does not give a clean spot, repeat until it does. In extreme cases, the tube, and possibly the pump, may have to be cleaned with soap and water. C. Sticky action of the plunger can be Figure 7-25: CO2 analyzer Chapter 7 Combustion Rubber Connector Pump Discharge Valve Sampling Tube Pump Suction Valve Filter & Water Trap helped by coating the plunger cup with petroleum jelly (Vaseline) after wiping the cup and the bore of the body clean. 2. CO2 analyzer A. After about 200 samples have been measured with the analyzer, the fluid will begin to lose its strength. This can be checked by measuring a sample in the normal manner, after the height of the fluid is measured on the % CO2 scale, invert the instrument two more times, let it drain, and reread. If the % CO2 reading changes more than ½ a number, the fluid is becoming weak and should be replaced. B. The sampling pump should be checked for leaks in the following manner: 1. Place a finger over the end of the sampling tube and squeeze the rubber bulb. The bulb should stay collapsed. If it does not, an air leak exists between the bulb and the sampling tube, or the discharge valve in the rubber bulb is leaking, Figure 7-25. 2. Place a finger over the rubber connector at the other end of the pump and seal off the hole tightly. Apply moderate pressure to the rubber bulb. If the bulb cannot hold pressure, a leak exists between the bulb and the rubber connector or the suction valve in the rubber bulb is leaking. C. Any evidence of fluid leakage from the analyzer should be checked. Such leakage is an indication of possible air leaks in the analyzer, which will give inaccurate CO2 readings. D. If the CO2 scale will not slide low enough to adjust the zero setting, it may be necessary to add water or more KOH fluid to bring up the fluid level. Add 2 or 3 drops of tap water into the space around the valve in the top of the analyzer. Depress the valve and release it several times, allow the water to drain down, and then check fluid level. If the level is still too low, add 2 or 3 more


NORA Oilheat Technicians Manual
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