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Refrigerant types and Pressure
Refrigerant Types
Refrigerants are the working fluids used in HVAC and refrigeration systems to transfer heat. Different types have been used over the years, with some common ones listed below:
Common Refrigerants
| Type | R-Number | Description | Usage |
|---|---|---|---|
| R-22 (Freon) | R-22 | Hydrochlorofluorocarbon (HCFC); phased out due to ozone depletion | Older systems, now being replaced |
| R-410A | R-410A | Hydrofluorocarbon (HFC); ozone-friendly, higher pressure | Modern air conditioners and heat pumps |
| R-134a | R-134a | Used in refrigeration and automotive systems | Refrigeration, automotive |
| R-32 | R-32 | HFC with lower GWP; more efficient, higher pressure | Newer HVAC systems |
| R-404A, R-507A | Various | Used in commercial refrigeration | Commercial applications |
| R-454B | R-454B | HFO/HFC blend; low GWP, efficient, ozone-friendly | Newer HVAC systems as a replacement for R-410A |
Environmental Considerations
- R-22 is being phased out due to ozone depletion potential.
- R-410A and R-32 are more environmentally friendly options.
- R-454B offers low GWP and is gaining popularity as a replacement for R-410A.
Refrigerant Pressure
Pressure Types
- Suction Pressure: Low-pressure side; varies with temperature.
- Head (Discharge) Pressure: High-pressure side; varies with condenser temperature.
Typical Pressure Ranges
| Refrigerant | Low-Side Pressure (psig) | High-Side Pressure (psig) | Notes |
|---|---|---|---|
| R-22 | 60-70 psig (at ~40°F) | 200-250 psig (at ~105°F) | Older systems, lower pressures |
| R-410A | 100-130 psig (at ~40°F) | 400-450 psig (at ~105°F) | Higher operating pressures |
| R-32 | Similar to R-410A, slightly higher | Slightly higher than R-410A | Higher efficiency, higher pressure |
| R-454B | Approximately 120-130 psig (at ~40°F) | 400-430 psig (at ~105°F) | Similar to R-410A but with lower GWP |
Factors Affecting Pressure
- Temperature: Both suction and head pressures increase with higher temperatures.
- Refrigerant Charge: Undercharged or overcharged systems will show abnormal pressures.
- System Condition: Blockages or leaks can affect pressure readings.
Why Pressure Matters
- Proper pressure levels are crucial for efficient system operation.
- Abnormal pressures can indicate refrigerant leaks, blockages, or other issues.
- Pressure readings are vital diagnostics tools for technicians.



