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21 Cards in this Set
- Front
- Back
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What does an anemometer measure? |
Measures air velocity at outlets in feet per minute — readings should be taken over multiple different parts of the outlet and averaged |
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What does a flow hood measure? |
Air volume at a duct or outlet |
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What will a tachometer measure? |
Measures fan rpm |
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What does a manometer measure? |
Measures air pressure - represented in inches of water (wg) |
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Manometers can be used to measure pressure drops across what kinds of equipment? |
Coils, fans, filters, sections of ductwork, terminal devices |
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What kind of sensing device is used for manometers? |
A pitot tube |
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What is a psychrometer? |
A measuring tool for relative humidity - measures both wet and dry bulb temps |
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What are the 4 main components of the refrigeration cycle? |
Compressor, condenser, metering device, evaporator |
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What happens when pressure is increased by the compressor? |
The refrigerant condenses and gives off latent heat |
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What happens when pressure is increased by the compressor? |
The refrigerant condenses and gives off latent heat |
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What happens when pressure is reduced by the metering device? |
The refrigerant evaporates and absorbs heat |
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When dealing with refrigeration what is the saturation temperature? Saturated liquid |
Refrigerant turns to vapour above this point nd turns to liquid below it Contains all the heat it can hold at that pressure and not vaporize |
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What is a saturated vapor? |
Contains just the amount of heat that keeps it from becoming liquid at that temp |
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What removes moisture and foreign particles form the system? |
Liquid line filter drier |
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What does the compressor do in the system? |
Moved the refrigerant Adds pressure to the refrigerant Divided high pressure side from the low pressure side Converts low pressure super vapor to High pressure superheated vapor |
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The refrigerant cycle |
Back (Definition) |
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What does the metering device do? |
Separates high pressure side from the low pressure |
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What does the condenser do? |
Transfer heat from the hot refrigerant in the coil to the surrounding air. As the refrigerant cools heat is released to the outside air. As it cools refrigerant condenses from a gas to a liquid |
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What does the evaporator in the cycle? |
Performs the cooling function of the system. The low pressure allows the liquid to turn to gas. This change of state absorbs heat from the surrounding indoor air |
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Gshs |
Dhsh |
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How many BTU’s in a 1 ton refrigeration unit |
12000 |
