HVAC Metering Devices Practice Test 2026 - Free HVAC Practice Questions and Study Guide

The function of adjusting the thermal expansion valve (TXV) in relation to superheat is crucial for increasing system efficiency. The TXV regulates the flow of refrigerant into the evaporator based on the temperature of the refrigerant leaving the evaporator. Proper superheat ensures that the refrigerant is fully vaporized before it enters the compressor. By adjusting the TXV, technicians can control the amount of refrigerant allowed into the evaporator, which can help maintain the proper superheat level. When superheat is optimal, it ensures that only vapor enters the compressor, which enhances the system's efficiency and performance.

Maintaining the correct superheat is essential for the overall functioning of the HVAC system. Too low a superheat can lead to liquid refrigerant entering the compressor, risking damage, while too high a superheat can indicate insufficient refrigerant flow, leading to inadequate cooling. Therefore, proper TXV adjustment contributes directly to operational efficiency by ensuring the system operates within its designed parameters.