How to Recharge a Mini Split with R22: A Comprehensive Guide

Recharging a mini-split air conditioner with R22 refrigerant can be a delicate and technical process, but with the right tools and knowledge, it can be done safely and effectively. In this comprehensive guide, we’ll walk you through the step-by-step process of recharging a mini-split with R22, providing detailed information and expert-level insights to ensure a successful outcome.

Necessary Tools and Equipment

Before you begin the recharging process, make sure you have the following tools and equipment on hand:

  1. Manifold Gauge Set: This essential tool allows you to measure the pressure and temperature of the refrigerant in the system, which is crucial for determining the proper charge.
  2. R22 Refrigerant: The specific refrigerant required for your mini-split system. It’s important to use the correct type and amount of refrigerant.
  3. Adjustable Wrench: For tightening and loosening the connections on the manifold gauge and refrigerant lines.
  4. Thermometer: To measure the temperature of the refrigerant lines and determine the superheat.
  5. Safety Gear: Gloves, goggles, and a well-ventilated work area to protect yourself during the recharging process.

Step-by-Step Recharging Process

how do you recharge a mini split with r22Image source: Flickr

  1. Turn Off the Air Conditioner: Ensure that the mini-split system is turned off and the thermostat is set to its coolest setting.
  2. Remove the Valve Caps: Locate the R22 refrigerant valve caps on the pipes that enter the outdoor unit and remove them.
  3. Connect the Manifold Gauge: Attach the left-hand hose of the manifold gauge to the large pipe valve and the right-hand hose to the small pipe valve.
  4. Purge the Manifold Hoses: Open each handle on the manifold gauge for a second to purge any air from the hoses.
  5. Connect the Refrigerant Hose: Attach the middle hose of the manifold gauge to the R22 refrigerant container.
  6. Flip the Refrigerant Container: Turn the R22 container upright and open the valve to allow the refrigerant to flow into the system.
  7. Monitor the Pressure Gauges: Watch the left and right pressure gauges on the manifold to see when the pressure equalizes.
  8. Adjust the Pressure: If the left-hand gauge reads above 60 psi, briefly open the left-hand gauge handle to drop the pressure.
  9. Allow the System to Run: Let the mini-split system run for 3-5 minutes to stabilize the refrigerant flow.
  10. Measure the Superheat: Use a thermometer to measure the temperature 6 inches from the valve on the large pipe. This will give you the superheat reading.
  11. Analyze the Superheat: Compare the temperature reading to the left-hand gauge pressure and check the pressure/temperature (P/T) chart. Refer to the manufacturer’s recommendations for the optimal superheat range.
  12. Add or Remove Refrigerant: If the superheat is 20+ degrees above the P/T chart reading, add more R22 refrigerant until the superheat is between 8 and 18 degrees. A superheat of 12 degrees is often optimal (70 psi at 85 degrees). If the superheat is below 7 degrees, it indicates an overcharge, and you’ll need to remove some refrigerant.
  13. Finalize the Recharge: Once the superheat is within the optimal range, close the R22 container valve, disconnect the hoses, and replace the valve caps.

Considerations and Cautions

  • R22 refrigerant is no longer being produced and is considered an ozone-depleting substance. It is illegal to import or produce new R22 in many countries.
  • If your mini-split system uses R22, it’s recommended to consult with a professional HVAC technician about converting the system to a more environmentally friendly refrigerant or replacing the entire unit.
  • Improper recharging can damage the compressor or other components of the mini-split system. It’s crucial to follow the manufacturer’s guidelines and use the correct tools and techniques.
  • Handling refrigerants can be hazardous, as they can be flammable and toxic. Ensure proper ventilation and wear appropriate personal protective equipment (PPE) during the recharging process.


Recharging a mini-split with R22 refrigerant requires a thorough understanding of the process and the necessary tools and equipment. By following the step-by-step guide provided in this comprehensive manual, you can safely and effectively recharge your mini-split system, ensuring optimal performance and energy efficiency. However, it’s important to consider the environmental and legal implications of using R22 and to consult with a professional HVAC technician for the best long-term solution for your mini-split system.


  1. How to Recharge a Mini Split with R22 Refrigerant
  2. How to Recharge a Mini Split Air Conditioner
  3. How to Refill an R22 Air Conditioner