Start with the equipment data plate or the manufacturer's service documentation. It should identify the approved refrigerant, such as R410A, R32, R454B, R404A, R407C, R448A, R22 or R134A.

Not simply by changing the refrigerant. R410A, R32 and R454B have different operating characteristics and equipment requirements.

R32 and R454B are also classified as A2L refrigerants and equipment designed for them incorporates requirements that may differ from equipment designed around R410A.

Only use a refrigerant that the equipment manufacturer specifically approves for that system.

All three may be encountered in air-conditioning and heat-pump applications, but they are different refrigerants and should not be treated as direct substitutes.

• R410A: widely used in many existing residential and commercial A/C systems.
• R32: used in newer equipment specifically engineered for R32.
• R454B: used in newer systems designed and approved for R454B.

Always follow the refrigerant designation shown on the unit rather than choosing based only on the type of equipment.

No. Different refrigerant types should not be mixed unless a specific manufacturer-approved service procedure explicitly calls for it.

Mixing refrigerants can alter operating pressures, temperatures and performance, complicate recovery and make proper servicing difficult.

A product listed as a 25 lb or 30 lb cylinder normally refers to the refrigerant's stated net contents rather than the total shipping weight of the cylinder.

The complete package will weigh more because the cylinder, valve and packaging add additional weight.

Always refer to the product label for the exact net contents of the cylinder you receive.

Not necessarily. Refrigerant charge requirements vary significantly depending on the equipment, capacity, line-set length and system design.

The required factory charge is normally shown on the equipment data plate or in the manufacturer's installation and service documentation.

The correct charging procedure depends on the equipment and manufacturer instructions.

Refrigerant weight is commonly an important part of the charging process, while operating measurements such as superheat, subcooling, temperature and pressure may also be required depending on the system.

Manufacturer service information should always take priority over a generic charging rule.

Every refrigerant has its own pressure-temperature relationship. The pressure expected in a system therefore depends on the refrigerant, system conditions and operating temperatures.

This is why pressure readings from one refrigerant should not be used as a reference for a different refrigerant.

Professional service work may require equipment such as:

• Refrigerant-compatible gauges
• Properly rated hoses and fittings
• Refrigerant charging scale
• Vacuum pump
• Micron gauge
• Leak-detection equipment
• Recovery machine and recovery cylinder
• Temperature measurement tools

Systems using A2L refrigerants may require tools and procedures specifically suitable for A2L service.

Refrigerant loss can indicate a leak. Simply adding more refrigerant without determining why the charge was lost may leave the underlying problem unresolved.

A qualified technician should evaluate the system, locate and address leaks when required, confirm system integrity and recharge according to the manufacturer's service procedure.

Follow all instructions printed on the cylinder and supplied by the refrigerant manufacturer.

Cylinders should generally be protected from excessive heat, physical damage and unauthorized handling and kept in an appropriate, well-ventilated storage location.

Additional precautions apply to refrigerants with flammability classifications such as A2L products.

Existing equipment originally designed for R22 may continue to require R22 or an approved retrofit solution during service.

Refrigerant selection should be based on the equipment, manufacturer guidance, applicable service procedures and current regulatory requirements.

Do not install a replacement refrigerant into an R22 system solely because it appears to have similar operating characteristics.

A2L is a refrigerant safety classification associated with lower flammability characteristics compared with more highly flammable refrigerant classes.

Equipment intended for an A2L refrigerant is designed around applicable safety requirements. Technicians should use appropriate procedures, tools and equipment when working with these systems.

Refrigerant intended for use in stationary refrigeration and air-conditioning equipment is subject to U.S. EPA refrigerant sales requirements.

Section 608 technician certification or other qualifying purchaser documentation may be required depending on the transaction and intended application.

Customers are responsible for meeting applicable federal, state and local purchasing, handling, recovery and service requirements.