R22 PT Chart: A Comprehensive Guide to Pressure and Temperature Dynamics

R22, also known as chlorodifluoromethane, has long been a staple refrigerant in air conditioning and refrigeration systems. However, due to its adverse impact on the ozone layer, R22 is gradually being replaced by more environmentally friendly alternatives. Despite the ongoing phase-out, numerous older systems still rely on R22, making it crucial for technicians to grasp the nuances of the R-22 PT chart.

Understanding the R22 PT Chart

The R22 PT chart is a visual representation of the intricate relationship between pressure and temperature specific to R22 refrigerant. This graph serves as a fundamental tool for determining optimal operating pressures in R22 systems. Additionally, technicians employ the chart for troubleshooting purposes, identifying issues such as insufficient cooling due to low pressure. By consulting the R22 PT chart, technicians can pinpoint the correct pressure levels and address problems by adding the necessary refrigerant.

Temperature (°F)Temperature (°C)Pressure (psig)
-60°F-51.1°C11.9 psig
-55°F-48.3°C9.2 psig
-50°F-45.6°C6.1 psig
-49°F-45.0°C5.4 psig
-48°F-44.4°C4.8 psig
-47°F-43.9°C4.1 psig
-46°F-43.3°C3.4 psig
-45°F-42.8°C2.7 psig
-44°F-42.2°C1.9 psig
-43°F-41.7°C1.2 psig
-42°F-41.1°C0.4 psig
-41°F-40.6°C0.2 psig
-40°F-40.0°C0.6 psig
-39°F-39.4°C1.0 psig
-38°F-38.9°C1.4 psig
-37°F-38.3°C1.8 psig
-36°F-37.8°C2.2 psig
-35°F-37.2°C2.6 psig
-34°F-36.7°C3.1 psig
-33°F-36.1°C3.5 psig
-32°F-35.6°C4.0 psig
-31°F-35.0°C4.5 psig
-30°F-34.4°C4.9 psig
-29°F-33.9°C5.4 psig
-28°F-33.3°C5.9 psig
-27°F-32.8°C6.4 psig
-26°F-32.2°C6.9 psig
-25°F-31.7°C7.4 psig
-24°F-31.1°C8.0 psig
-23°F-30.6°C8.5 psig
-22°F-30.0°C9.1 psig
-21°F-29.4°C9.6 psig
-20°F-28.9°C10.2 psig
-19°F-28.3°C10.8 psig
-18°F-27.8°C11.4 psig
-17°F-27.2°C12.0 psig
-16°F-26.7°C12.6 psig
-15°F-26.1°C13.2 psig
-14°F-25.6°C13.9 psig
-13°F-25.0°C14.5 psig
-12°F-24.4°C15.2 psig
-11°F-23.9°C15.9 psig
-10°F-23.3°C16.5 psig
-9°F-22.8°C17.2 psig
-8°F-22.2°C17.9 psig
-7°F-21.7°C18.7 psig
-6°F-21.1°C19.4 psig
-5°F-20.6°C20.1 psig
-4°F-20.0°C20.9 psig
-3°F-19.4°C21.7 psig
-2°F-18.9°C22.4 psig
-1°F-18.3°C23.2 psig
0°F-17.8°C24.0 psig
1°F-17.2°C24.9 psig
2°F-16.7°C25.7 psig
3°F-16.1°C26.5 psig
4°F-15.6°C27.4 psig
5°F-15.0°C28.3 psig
6°F-14.4°C29.2 psig
7°F-13.9°C30.1 psig
8°F-13.3°C31.0 psig
9°F-12.8°C31.9 psig
10°F-12.2°C32.8 psig
11°F-11.7°C33.8 psig
12°F-11.1°C34.8 psig
13°F-10.6°C35.8 psig
14°F-10.0°C36.8 psig
15°F-9.4°C37.8 psig
16°F-8.9°C38.8 psig
17°F-8.3°C39.9 psig
18°F-7.8°C40.9 psig

Exploring the Two-Dimensional R22 Pressure Temperature Chart

The R22 PT chart typically presents a two-dimensional layout, with temperature on the x-axis and pressure on the y-axis. This graphical representation facilitates the determination of R22 pressure at various temperatures and vice versa, streamlining the troubleshooting process for HVAC professionals.

Optimal Operating Pressures for R22

In a well-functioning HVAC system, the pressure on the suction side should ideally fall within the range of 55 to 75 psi, while the discharge side should be maintained between 235 and 255 psi. These values are contingent on the outdoor ambient temperature.

R22 Pressures Across Different Outdoor Temperatures

To provide a clearer picture, let’s delve into the recommended R22 pressures on specific days:

  1. 65-Degree Day:
  • Suction Side: 50-60 psi
  • Discharge Side: 250-265 psi
  1. 70-Degree Day:
  • Suction Side: 55-65 psi
  • Discharge Side: 255-270 psi
  1. 80-Degree Day:
  • Suction Side: 58-68 psi
  • Discharge Side: 260-275 psi
  1. 85-Degree Day:
  • Suction Side: 60-70 psi
  • Discharge Side: 265-280 psi
  1. 90-Degree Day:
  • Suction Side: 62-72 psi
  • Discharge Side: 270-285 psi
  1. 95-Degree Day:
  • Suction Side: 65-75 psi
  • Discharge Side: 275-290 psi
  1. 100-Degree Day:
  • Suction Side: 68-78 psi
  • Discharge Side: 280-295 psi

Physical Properties of R22

Understanding the physical properties of R-22 is integral to comprehending its behavior in various conditions:

  • Chemical Formula: Chlorodifluoromethane (CHCl2F)
  • Boiling Point: -41.5°F (-50.3°C)
  • Critical Temperature: 205.1°F (96.2°C)
  • Critical Pressure: 723.7 psia (50.2 bar)
  • Heat of Vaporization: 100.5 BTU/lbm (234.1 kJ/kg)
  • Molecular Weight: 86.

Exploring R22 PT Chart Applications

Advanced Troubleshooting Techniques

Beyond its foundational role, the R22 PT chart proves invaluable for advanced troubleshooting. Technicians can pinpoint subtle issues by analyzing deviations from standard pressure-temperature relationships. For instance, unexpected high discharge pressures might indicate a blockage, prompting a closer inspection of components.

Retrofitting and System Upgrades

With the phase-out of R22, many systems are undergoing retrofitting or upgrades to accommodate environmentally friendly alternatives. The R22 PT chart is a guiding tool in this process, aiding technicians in adjusting pressures for new refrigerants and ensuring seamless transitions without compromising system efficiency.

Adapting to Dynamic Environmental Conditions

Understanding R22 pressures across different ambient temperatures is crucial for HVAC professionals working in diverse climates. As outdoor temperatures fluctuate, technicians must adjust system pressures to maintain optimal performance. The R22 PT chart becomes a dynamic companion, allowing for real-time adjustments based on environmental variables.

Environmental Responsibility and Future Trends

The transition away from R22 aligns with broader environmental initiatives. As the industry embraces eco-friendly refrigerants, technicians play a pivotal role in mitigating the impact of climate change. Staying informed about alternative refrigerants and their corresponding pressure-temperature characteristics is essential for future-proofing HVAC systems.

Emerging Refrigerants: A Glimpse into the Future

Keeping pace with technological advancements, HVAC professionals must anticipate the characteristics of emerging refrigerants. The R22 PT chart model can serve as a prototype for charts related to new refrigerants, emphasizing the importance of a versatile skill set in adapting to evolving industry standards.

Educational Outreach and Training

In the spirit of knowledge dissemination, HVAC technicians can leverage the R22 PT chart as a teaching tool. Educational outreach programs can benefit from its visual simplicity, helping train the next generation of technicians. By imparting a deep understanding of pressure-temperature dynamics, professionals contribute to a skilled workforce well-versed in the evolving landscape of refrigerants.

Interactive Digital Tools for Technicians

In the digital age, translating the R22 PT chart into interactive tools can enhance accessibility and ease of use. Mobile applications or web-based interfaces that dynamically plot pressure-temperature relationships based on real-time data can empower technicians in the field, fostering efficiency and precision.

Regulatory Compliance and Documentation

As the industry evolves, adherence to changing regulations becomes paramount. Technicians armed with a comprehensive understanding of the R22 PT chart are better equipped to navigate regulatory shifts. Accurate documentation of pressure-temperature readings ensures compliance with evolving environmental standards and contributes to a culture of transparency and accountability.

Conclusion: A Holistic Approach to Refrigeration Dynamics

The R22 PT chart, initially a tool for basic diagnostics, evolves into a multifaceted instrument for HVAC professionals. Beyond immediate applications in troubleshooting and system optimization, its adaptability to changing environmental norms and emerging technologies positions it as a cornerstone in the industry’s evolution. As the global community moves towards sustainable practices, technicians mastering the intricacies of refrigeration dynamics, as exemplified by the R22 PT chart, stand at the forefront of a greener and more efficient future.


Mastering the R-22 PT chart is indispensable for HVAC technicians dealing with systems still reliant on this refrigerant. As environmental considerations drive the phase-out of R-22, staying adept at interpreting pressure-temperature dynamics ensures the continued effective operation of older systems. By adhering to recommended pressures across diverse ambient temperatures, technicians can optimize R-22 systems, enhancing both performance and longevity. Embracing environmentally conscious practices and staying informed about alternative refrigerants will be key as the industry evolves beyond R-22.

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