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NORA Oilheat Technicians Manual

100+ ppm. Evacuate the home (including yourself!) and contact emergency medical services (911). Do not attempt to ventilate the space. Short-term exposure to these levels can cause permanent physical damage. Carbon monoxide is released into homes by vent blockage, flue pipe damage, heat exchanger cracks, and restricted air supply into the house. This last problem is progressively getting worse as new homes become tighter in their construction, and many homeowners are weather stripping and insulating their older homes. Most homes have a number of devices such as exhaust fans, clothes dryers, and fireplaces, that remove air from the home. This suction is often stronger than the suction of the heating system’s chimney or power vent. This back drafting causes the emissions from the heating system, the water heater, gas ovens, gas stoves, gas dryers, and wood stoves or fireplaces to enter the living area and elevate CO levels. Oilheat’s CO warning signs If you see smoke near the burner, dark smoke coming from the chimney, or smell a sharp raw oil smell, the burner is probably producing unacceptable levels of carbon monoxide. With insufficient combustion air, oilburners usually produce elevated smoke levels before high CO levels are reached. This smoke is a warning signal. The result is that the danger from high CO levels is much lower from oilburners than any other hydrocarbon burner. However, if oilburners are operated with too much combustion air, it chills the flame and creates CO with no smoke! Improper nozzle to air patterning can also produce CO. What to watch out for CO is odorless and tasteless, therefore in 7-8 Combustion order to detect its presence, we perform combustion tests and look for other clues for combustion or ventilation problems such as: • Sharp gas or oil smell • Stale or stuffy air • Soot, rust, or scale build-up on or around appliances and vents • Loose or disconnected chimney or vent connections • Debris or soot falling from chimney, fireplace, or appliance • Excessive moisture on the inside of windows or walls • Chalky white powder forming on the chimney or vent • Visible smoke in the living space Light off CO levels: High CO levels at light off may be an indication of rough or delayed ignition, warranting further investigation. The CO readings will peak on startup, then dramatically drop. CO readings should stabilize within 10 minutes of operation and should never be rising during operation. Mechanical problems and CO: If the appliance being tested has sufficient combustion air and is still producing higher than acceptable CO air-free levels, it could be a mechanical problem. Inspect the burner for cleanliness, proper alignment, fuel pressures, and evidence of impingement. Impingement occurs when the flame hits an object that has sufficient mass to transfer enough heat from the flame to cause low flame temperatures and incomplete combustion. This can be as simple as a screw poking into the heat exchanger or as major as a collapsed refractory. Missing burner covers, improper air band adjustment or oil pressures can also contribute to higher than normal CO levels. Chapter 7 Combustion


NORA Oilheat Technicians Manual
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