Which instrument is typically used to measure the temperature of refrigerants?

The correct instrument to measure the temperature of refrigerants in a typical refrigeration system is a manifold gauge set. This set includes two pressure gauges and usually a temperature scale that allows the operator to correlate the pressure readings with corresponding temperatures. Refrigeration systems often rely on the relationship between pressure and temperature of the refrigerant, as this is defined by thermodynamic principles.

The manifold gauge set enables a technician to quickly assess the system’s performance by providing simultaneous readings of both high and low-side pressures and their corresponding temperatures, which are essential for diagnosing system performance and efficiency.

The other options, while relevant to refrigeration, do not serve the specific purpose of measuring refrigerant temperatures as directly as a manifold gauge set does. For example, a thermometer is suitable for measuring temperature in general scenarios, but it doesn't provide the nuanced correlation between pressure and refrigerant temperature necessary in refrigeration systems. A pressure gauge only measures pressure, and a flow meter measures the flow rate, neither of which gives direct temperature readings.