Power Engineering 5th Class QNS

Power Engineering 5th Class QNS An agency or code with which fittings must comply is: Choose one answer. a. Health and Safety Code b. Fittings and Boiler Parts Act c. Boiler Repair Code d. Plumbing Gas Act e. ASME Code - ANS e Hot water heating boilers have stop valves in their supply and return piping: Choose one answer. a. To allow for better warm ups b. To prevent water from entering another in-service unit c. So that each boiler can have separate water treatment d. So that the boiler can be drained without draining the system e. To permit annual maintenance - ANS d An expansion tank is used to: Choose one answer. a. Dampen pulsations in the water pressure b. Increase water temperature c. Allow for the expansion of the water d. Provide more efficient water circulation e. Allow free expansion of the steam - ANS c How many pressure relief valves shall a hot water heating boiler have? Choose one answer. a. None b. At least one c. At least two d. At least three e. At least four - ANS b The scale on the dial of the pressure or altitude gauge on a hot water heating boiler shall be graduated to not more than _____ times the pressure at which the safety relief valve is set. Choose one answer. a. 1.5 b. 2 c. 2.5 d. 3 e. 3.5 - ANS e Boiler stop valves shall be: Choose one answer. a. Always of the outside screw and yoke design b. Globe valves c. Identified with durable tags d. Installed on horizontal piping only e. Throttled during operation - ANS c The scale on the dial of the pressure or altitude gauge on a hot water heating boiler shall be graduated approximately to not less than _____ times the maximum allowable working pressure. Choose one answer. a. 0.5 b. 1 c. 1.5 d. 2 e. 2.5 - ANS c If a hot-water heating boiler has an automatic fill valve, and is requiring a lot of makeup water, this may indicate: Choose one answer. a. The expansion tank is empty. b. There is probably a leak in the system c. There has been a drastic change in the water quality d. The return pumps are not working e. The flow meter is not working properly - ANS b The pressure relief valve on a hot water boiler: Choose one answer. a. Should be installed on the boiler or close to it b. Can be installed anywhere in the system c. Must be at least 51 mm pipe size d. Does not require annual checking or testing e. Can be installed with an isolation valve - ANS a The temperature indicator of a hot water boiler should indicate water temperature: Choose one answer. a. At the boiler inlet b. In the expansion tank c. Midway through the system d. At the boiler outlet e. In the boiler - ANS d When too much air has been absorbed by water in the expansion tank of a closed system, the tank must be: Choose one answer. a. Attached to an air separator b. Filled c. Removed d. Drained e. Replaced - ANS d An automatic fill valve for a hot water boiler: Choose one answer. a. Will maintain maximum system pressure at all times b. Operates to maintain a constant boiler water level c. Is not mandatory d. Operates to maintain a constant expansion tank level. e. Can be used with an open tank system - ANS c In a closed expansion tank system an air separator: Choose one answer. a. Removes air from the system b. Is installed at the boiler inlet c. Is installed at the boiler outlet d. Directs air into the expansion tank e. Removes air from the expansion tank - ANS d A pressure or altitude gauge for a hot water heating boiler: Choose one answer. a. Must be calibrated in kPa b. Shall have a dial scale at least three times the maximum allowable working pressure c. Does not require a siphon d. Must have a temperature dial e. Must be of 51 mm pipe size - ANS c A closed type expansion tank in a hot water heating system must: Choose one answer. a. Be full of water at all times b. Have a vent open to atmosphere at all times c. Be located three meters above the boiler d. Be located no higher than the top of the boiler e. Be partially filled with air at all times - ANS e A closed expansion tank is often equipped with: Choose one answer. a. A gauge glass b. A pressure relief valve c. An automatic fill valve d. A circulating pump e. A thermometer - ANS a When a closed type expansion tank on a hot water boiler is completely filled with water and the water in the system is raised in temperature so that it expands, the result will be that the: Choose one answer. a. Circulating pumps cavitate b. Pressure build up opens the safety relief valve c. Heating system becomes noisy d. Circulation pump will stop e. The boiler water will back-up into the potable water system - ANS b The entrained air in a hot water heating system is directed to the: Choose one answer. a. Relief valve b. Boiler c. Radiator vents d. Expansion tank e. Atmosphere - ANS d An altitude gauge on a hot water heating boiler is used to indicate: Choose one answer. a. Expansion tank temperature b. Boiler temperature c. Furnace draft d. The highest level of water in the system e. The height of the boiler - ANS d When a closed expansion tank is used and the system is cold a) the auto fill valve will maintain a system minimum pressure b) the tank level will be high c) there will be no air in the tank d) the possibility of air in the system will be high e) the tank should be manually filled - ANS b Siphon is not required between a pressure or an altitude gauge and a hot water boiler since these boilers are a) filled with steam b) partially filled with steam c) partially filled with air d) filled with water e) filled with water and air mixtures - ANS d The lever handle of the shut-off cock between a pressure or altitude gauge and a hot water boiler should be __________ to the pipe in which it is located when the cock is open. a) perpendicular b) parallel c) adjacent d) opposite e) tangent - ANS b The dial of a pressure gauge on a hot water boiler indicating SI units can be graduated in a) metres of mercury b) mm of water c) mPa d) psi e) kPa - ANS e When the pressure pointer of a closed system reads lower than the altitude pointer the a) system is full of water b) expansion tank level will be high c) boiler is being over-fired d) gage is faulty e) system requires water - ANS e Hot water heating boilers must be equipped with a a) thermometer b) fusible plug c) return trap d) blow down tank e) steam pressure gage - ANS a With the fusible plug type of temperature relief device, the fusible plug will melt at __________ degrees Celsius and allow hot water to escape. a) 131 b) 121 c) 101.3 d) 100 e) 99 - ANS e The expansion and contraction rod type of temperature relief device will open the valve at __________ degrees Celsius and close it at __________ degrees Celsius. a) 99 and 80 b) 100 and 71 c) 101.3 and 75 d) 99 and 71 e) 100 and 80 - ANS d A hot water boiler is protected from over pressure by means of a) a safety pop valve b) a high limit pressure control c) an expansion valve d) an air release valve e) a safety relief valve - ANS e During warm-up of a cold hot water boiler excessive pressure build-up is prevented by a) a very slow warm-up b) an expansion tank c) a pressure relief valve d) opening the boiler outlet valve e) venting the system - ANS b