ESCO Air Conditioning Practice Exam

The oil pressure safety switch is operated by the difference between which pressures?

1. Condenser pressure and evaporator pressure

2. Crankcase pressure and oil pump pressure

3. Liquid line pressure and discharge line pressure

4. Suction line pressure and liquid line pressure

The correct answer is: Condenser pressure and evaporator pressure

The oil pressure safety switch is a component of an oil system in a refrigeration unit. It is designed to shut off the compressor if the oil pressure drops below a certain level. This prevents damage to the compressor and other components of the system. Based on the question, the switch is operated by the difference between two pressures. Option A, which is the correct answer, states that the switch is operated by the difference between the condenser pressure and evaporator pressure. This makes sense because the oil pressure in the system will generally decrease as it moves from the high pressure side (condenser) to the low pressure side (evaporator). Therefore, the difference between these two pressures can serve as an indication of the overall oil pressure in the system. The other options, B, C, and D, are incorrect. Option B mentions the crankcase pressure and oil pump pressure as the two pressures that operate the switch. While these may be important pressures in the oil system, they do not directly control the operation of the safety switch. Options C and D mention pressures that are not directly related to the oil system at all. Overall, the correct answer highlights the importance of properly maintaining the oil pressure in a refrigeration unit to ensure safe and