How can you tell if a system uses R-410A versus R-22 from labeling and service data, and why does it matter for pressures?

• A. Use temperature measurement only; Pressure is independent.
• B. Check outdoor unit nameplate or service label; R-410A uses higher pressures than R-22; incorrect pressures can cause poor performance or damage.
• C. Look at color of wires; R-410A uses higher voltages.
• D. Check indoor unit nameplate for refrigerant type; R-22 and R-410A use the same pressures.

Answer: (B)

Identifying the refrigerant type comes from labels and service data on the unit. Check the outdoor unit nameplate or the service label—the refrigerant listed there tells you whether the system is R-410A or R-22. Service data sheets also provide the specific pressure–temperature (P–T) charts and charge requirements for each refrigerant.

The reason this matters for pressures is that R-410A and R-22 have different pressure requirements at the same temperatures. R-410A operates at higher saturated pressures than R-22. If you use the wrong pressure data (or charge the system based on the other refrigerant), you can push the compressor and other components beyond their design limits, leading poor performance or damage. So reading the labeling for the refrigerant and following its corresponding pressure data is essential for safe, effective operation.