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9 Cards in this Set
- Front
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Glycol coils using ethylene glycol: 1) Are not recommended for use in heating and air conditioning systems in the food industry 2) Give reasonable heat transfer efficiency at low glycol velocity 3) Use direct fired boilers as their heat source 4) Do not use steam-glycol converters as their heat source 5) Are used only for heating purposes and are not used for cooling purposes |
Are not recommended for use in heating and air conditioning systems in the food industry |
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The inverted bucket steam trap is: 1) Used when the coil steam pressure is lower than 172 kPa or 25 psig 2) Used when the flow is modulated 3) Recommended when condensate flows by gravity into a return main at atmospheric pressure 4) More expensive than the F & T trap 5) Used when the coil steam pressure is higher than 172 kPa or 25 psig |
Used when the coil steam pressure is higher than 172 kPa or 25 psig |
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Which of the following statements about vacuum breakers is false? 1) The vacuum breaker must be installed before the control valve and as near as possible to the outlet connection of the coil 2) Vacuum breakers are essential for satisfactory functioning of the steam trap 3) Check valves used as vacuum breakers may be left open to the atmosphere 4) Check valves used as vacuum breakers may be connected to the return header 5) They are used to prevent freeze-ups caused by negative pressure in the coil |
The vacuum breaker must be installed before the control valve and as near as possible to the outlet connection of the coil |
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A modulating control valve: 1) Is not used to control steam coils at any air inlet temperature 2) Is used for steam coils when the entering air temperature is below 1.5ºC 3) Can be oversized 4) Is used for steam coils where the condensate is lifted to an overhead return 5) Can be used to control steam coils when the entering air temperature is above 1.5ºC |
Can be used to control steam coils when the entering air temperature is above 1.5ºC |
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For a glycol system using hot water as its heat source, which of the following statements is false? 1) The hot water supply valve will be opened to feed a constant flow of hot water to the converter 2) Provide flanges or unions and manual shutoff valves to facilitate coil removal 3) The flow switch automatically starts the glycol pump automatically after the hot water supply valve is opened 4) Hot water temperature should not exceed 100ºC 5) The temperature controller opens the hot water supply valve when the temperature outside drops to 10ºC |
The flow switch automatically starts the glycol pump automatically after the hot water supply valve is opened |
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In a hot water coil, which of the following is not included for providing a good guideline for the correct application of the system with minimal possibility of freeze-up? 1) A constant flow of water should be fed to the coil 2) The water velocity should exceed 0.9 m/s 3) The air velocity should exceed 10 m/s 4) The water temperature should be maintained at a reasonable pre-set temperature 5) Positive air venting of the coil is essential |
The air velocity should exceed 10 m/s |
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The flow arrangement best suited for hot water coils used to heat sub-freezing air is: 1) The half serpentine 2) One in which the cold air enters the coil where the coldest water is flowing 3) The counter flow arrangement because it is more efficient 4) The triple bypass flow arrangement 5) The parallel flow arrangement because it gives better protection against freezing |
The parallel flow arrangement because it gives better protection against freezing |
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To prevent freezing of the steam coil when steam pressure at the coil inlet is too low or is lost: 1) Provisions are made to stop the fan and close the outdoor air dampers 2) The fan output is increasedIncorrect 3) A modulating steam control valve is installed at the coil inlet 4) A two-position steam control valve is installed at the coil inlet 5) A second preheat coil is installed at the outside air inlet |
Provisions are made to stop the fan and close the outdoor air dampers |
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Steam coil piping and trapping: 1) Is the same for hot water and glycol coils 2) Differs from the hot water and glycol coil because it carries more fluids: steam, air, water, and non-condensable gases 3) Can be supported directly by the coils 4) Only handles steam and non-condensable gases 5) Are installed in the horizontal position whenever possible |
Differs from the hot water and glycol coil because it carries more fluids: steam, air, water, and non-condensable gases |
