What are refrigeration and air-conditioning compressor heaters used for? (A) A) To prevent acid pitting. (B) B) To prevent refrigerant vaporization. (C) To reduce the amount of refrigerant in the oil. (D) D) To reduce the amount of entrained water in the receiver.

The correct answer is: **(C) To reduce the amount of refrigerant in the oil.** **Explanation:** In refrigeration and air-conditioning systems, compressor heaters are primarily used to manage the temperature of the compressor oil. When the system operates in low-temperature environments, the oil can become too viscous, making it difficult to circulate properly. Additionally, refrigerant can dissolve in the oil, and excessive refrigerant in the oil can lead to inefficiencies and potential compressor issues. By heating the compressor, the heater helps to: 1. **Lower Oil Viscosity:** Makes the oil less thick, ensuring it circulates smoothly within the compressor. 2. **Reduce Refrigerant Solubility:** Prevents excessive refrigerant from remaining dissolved in the oil, ensuring that the oil maintains its lubricating properties without being diluted by too much refrigerant. This ensures optimal compressor performance, reduces wear and tear, and prolongs the lifespan of the refrigeration or air-conditioning system. **Incorrect Options:** - **(A) To prevent acid pitting:** Acid pitting is more related to corrosion issues, which are typically managed through proper maintenance and material selection rather than compressor heaters. - **(B) To prevent refrigerant vaporization:** The compressor's role is to vaporize and compress the refrigerant, so preventing vaporization would counteract its primary function. - **(D) To reduce the amount of entrained water in the receiver:** While moisture management is important, compressor heaters are not primarily used for reducing water in the receiver. This is typically handled by other components like moisture separators or filters.