1. Look for the R-134a label. All R-134a air-conditioning systems will have a label that indicates the type of refrigerant used. This label is usually located on the front or side of the unit.
2. Check the service port. The service port for an R-134a system is different than the service port for other refrigerants. The R-134a service port has a smaller diameter and a different thread size.
3. Ask a professional. If you're not sure what type of refrigerant your air-conditioning system uses, you can ask an HVAC professional. They will be able to tell you if your unit uses R-134a or another refrigerant.
Here is a table summarizing the key differences between R-134a and other common refrigerants:
| Refrigerant | Service Port Diameter | Thread Size |
|---|---|---|
| R-134a | 1/4 inch | 1/4-inch SAE |
| R-22 | 5/16 inch | 5/16-inch SAE |
| R-410A | 1/4 inch | 5/16-inch SAE |
Note: R-22 is no longer being manufactured in the United States. However, it is still used in some older air-conditioning systems.
