Unit 23: Compressors Questions and Answers

Unit 23: Compressors Questions and Answers Which of the following best describes the function of a compressor? The compressor increases the pressure in the system from the low-side pressure to the high-side pressure. Five types of compressors are _____________. reciprocating, rotary, scroll, screw, and centrifugal Which of the following is true of HVACR compressors? a compressor cannot compress a liquid What would be considered a higher-than-normal temperature for a discharge gas line on a reciprocating compressor? 250°F Which compressor type uses pistons to compress the gas? Reciprocating Which compressor type uses tapered, machined gear components to trap the gas for compression? Screw Which style of compressor uses belts to turn the compressor? Open drive What would be done to increase the compressor speed on a belt-driven compressor? Increase drive pulley size Which of the following design factors can affect the efficiency of a reciprocating compressor? The valve plate design and clearance volume. A medium-temperature R-134a system that has a suction pressure of 22 psig and a discharge pressure of 185 psig would have a compression ratio of _________. 5.44 to 1 A direct-drive compressor typically runs at _______ rpm. 1750 or 3450 A piston, connecting rod, crankshaft, valves, valve plate, head, shaft seal, internal motor overload device, pilot-duty motor overload device, and coupling are parts that may be found in a ___________ compressor. reciprocating What effect does a slight amount of liquid refrigerant have on a compressor over a long period of time? It dilutes the oil and causes wear on any moving parts. What lubricates the refrigeration compressor? Oil What can the service technician do to keep the refrigeration system operating at peak efficiency? Clean the evaporator and condenser coils to keep pressures within design parameters. A __________ compressor is usually considered to be a low-side device because the suction gas is vented to the inside of the shell, including the crankcase. hermetic