Low Pressure Boiler License – Questions & Answers Name the most frequent cause for failure on cast iron boilers? ✔️Ans - cracking due to overheating (low water) or thermal shock What is the maximum size of safety valve permitted on a heating boiler?✔️Ans - 4 1/2 inches What is the function of a boiler vent? ✔️Ans - It is used to vent air from the boiler when filling with water or warming the boiler, and to prevent vacuum from forming when taking the boiler offline.What is the function of low water fuel cut-off? ✔️Ans - It shuts off the boiler burner in the event of a low water What is the function of the operating pressure control? ✔️Ans - An automatic device that controls the starting and stopping of the burner on steam pressure demand.Explain the term "water hammer". ✔️Ans - Banging cause by steam and water mixing in a steam line.What is the first thing a boiler operator must do when taking over a shift ?✔️Ans - Check the water level on all boilers that are online/working Name two pressure controls required on a steam heating boiler. ✔️Ans - Modulating pressure control, pressure control or ON/OFF conbustion control What determines the frequency of boiler blowdown? ✔️Ans - Feed water annalist What is an induced draft fan? ✔️Ans - Mechanical draft produced by a power driven fan located between the boiler and the chimney Steam boilers are required to have a steam gauge, what are hot water boilers required to have? ✔️Ans - Temperature Pressure Gauge 1 / 2
What is a compound gauge? ✔️Ans - It indicates pressure on one side and vacuum on the other Why are cross tees provided on water column piping? ✔️Ans - For inspection of steam and water lines for scale build-up What is the maximum pressure allowed on a cast iron sectional boiler?✔️Ans - 15psi What is meant by purging the furnace? ✔️Ans - To remove explosive combustibles from the furnace that could lead to a furnace explosion.The steam boiler component used to lower the concentration of dissolved
impurities in the boiler water is the: ✔️Ans - Blow-off connection.
To reduce corrosion in large hydronic heating systems, a gas cushion is recommended in the expansion tank consisting of. ✔️Ans - Nitrogen What is the maximum allowable working pressure of a boiler during hydrostatic testing? ✔️Ans - 150% If a 20-tooth pinion is turning at 120 rpm and the driven gear has 60 teeth, the driven gear is turning at:: ✔️Ans - 40 RPM A pH level of 7 C is an indication that the boiler water is: ✔️Ans - Neutral neither basic or acidic At sea level, atmospheric pressure is approximately ✔️Ans - 14.7 psi Specific gravity is the ratio of weight of a volume of a substance to the weight of the same volume of ✔️Ans - water Heat transfer can occur by ✔️Ans - conduction, convection, and radiation Water weighs ✔️Ans - 8.3 lb/gal Boiler safety valves should be repaired by a ✔️Ans - authorized safety valve repair company
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