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NORA Oilheat Technicians Manual

Heat to House Radiator Piping Flue Gas to Chimney Heated Water Return Chapter 13—Heating Systems 13-7 3. Do the ducts run through “cold” areas? Sometimes it is necessary to run ducts in unheated areas such as crawl spaces, garages or attics. When this situation occurs, the heat loss from the bare duct can cool the air coming out of the register. If this situation exists then the ducts should be insulated to stop this heat loss. Short cycling If the burner is short cycling or if the unit is regularly shutting off on high limit, the following should be checked: 1. Are controls set properly? Chapter 13 Heating Systems 2. Is blower operating? 3. Is fan belt broken or slipping? 4. Are pulleys slipping? 5. Are air filters plugged? 6. Are return air grills and ducts free of restriction? 7. Are supply registers and ducts free of restriction? 8. Is unit over firing? 9. Is the duct system designed to meet the requirements of the furnace? Hot water boilers and heating systems A hot water boiler is a heat exchanger that uses the heat from the oil flame to heat water. This heated water is piped to radiation in the building to supply space heating. The cooled water is then pumped back to the boiler where it is reheated. Figure 13-7 shows a basic hot water heating system. Usually the heated water leaves the boiler at about 160° to 180°F and returns at 140-160°F. Boiler designs Boilers are constructed from cast-iron or steel and can be either “wet base” or “dry base.” A wet base boiler has water surrounding the combustion chamber while a dry base boiler does not. The most common steel boiler is the “fire-tube” boiler in which hot combustion Figure 13-7: Basic hot water heating system Oilburner Combustion Chamber Boiler Heating Surface Water Water Pump Boiler Part II


NORA Oilheat Technicians Manual
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