ASE A7 HVAC Exam Graded A+

Tech A says that evacuating an AC system will remove air and moisture from the system. Tech B says evacuating an AC system removes dirt particles. Who is right? - ANSWER-A. Evacuating the system removes air and moisture. The receiver drier may contain a filter or strainer to catch and trap foreign particles and dirt, but this remains in the drier and is not removed during evacuation. There is a growling/rumbling noise at the AC compressor when the system is off and the engine is running. The noise stops when the system is turned on.Tech A says that a bad compressor bearing could be the cause. Tech B says that a bad compressor clutch bearing could be the cause. Who's correct? - ANSWER-B. The compressor clutch bearing allows the rotor/pulley assembly to spin independently of the compressor shaft when the AC is off. When the AC is on, the rotor/pulley assembly and the armature are locked together by the magnetic action of the compressor clutch coil. The readings on a manifold gauge are 5psi low and 80 psi high with the AC system operating at an ambient temp of 85 degrees Farenheit. What do the readings indicate? Normal operation, low refrigerant level, a restriction on the high side, or a damaged compressor? - ANSWER-B. Low pressure on both the high and low side indicates a low refrigerant charge. Recovery/recycling equipment must have shutoff valves located within 12 in of the hose's service ends so that: oil can be added to the refrigerant the unit can be isolated from the refrigerant source the filter can be changed without disconnecting the hoses refrigerant discharge can be kept to a minimum - ANSWER-D. According to the Clean Air Act, recovery/recycling equipment must have shutoff valves located within 12 in. of the hoses' service ends so that refrigerant discharge to the atmosphere is kept to a minimum. When recovering refrigerant from an AC system how long should the tech wait after the recover/recycle unit has been turned off to check residual pressure in the system? 1 minute 5 minutes 10 minutes 15 minutes - ANSWER-B. the tech should wait five minutes and watch the gauges to check for residual pressure. If there is, repeat the process to remove any remaining refrigerant until the AC system holds a stable vacuum for 5 min. A system with a low pressure on the low side and heavy frost accumulation on the inlet side of a TXV indicates: TXV stuck open