R22 PT Chart Calculator – Pressure Temperature for R22 (Free Tool)

R22 PT Chart Calculator: Pressure Temperature for R22 Refrigerant (Free Tool)

You are servicing an older air conditioner or heat pump. It uses R22 refrigerant. You need to check the charge. You measure pressure at the service port. What is the corresponding saturation temperature?

R22 (Freon) was the standard refrigerant for decades. Many systems still use it. Knowing the pressure-temperature relationship is critical for charging, troubleshooting, and maintenance.

Today, I give you a free R22 PT Chart Calculator.

You enter pressure (psig) or temperature (°F). The calculator shows the corresponding saturation temperature or pressure.

The calculator also shows:

• Saturation temperature for a given pressure
• Saturation pressure for a given temperature
• Superheat and subcooling guidance

Let me explain how R22 pressure-temperature works.

What is R22? (Simple Explanation)

R22 (chlorodifluoromethane) is a hydrochlorofluorocarbon (HCFC) refrigerant. It was widely used in air conditioners, heat pumps, and refrigeration systems from the 1950s until 2010.

Key properties:

• Ozone depletion potential (ODP) = 0.055
• Global warming potential (GWP) = 1,810
• Operating pressure is about 50-60% lower than R410A
• Single-component refrigerant (no glide)
• Being phased out due to ozone depletion

Typical pressures:

• Low side (suction): 60-80 psig (35-45°F saturation)
• High side (discharge): 180-250 psig (100-120°F saturation)

Why This R22 PT Chart Calculator Matters

Here is why you need a PT calculator for R22.

Reason 1: Older systems still in use

Millions of R22 systems are still operating. They need service and maintenance.

Reason 2: Charging systems

To charge a system correctly, you need to know the saturation temperature at a given pressure. Use the PT chart to find target subcooling or superheat.

Reason 3: Troubleshooting

Low suction pressure could indicate low charge, restriction, or evaporator issues. High head pressure could indicate overcharge, dirty condenser, or non-condensables.

Reason 4: Drop-in replacements

When replacing R22 with alternatives (R407C, R422B, R438A), you need to adjust pressure expectations. The PT chart helps.

Reason 5: Safety

R22 operates at lower pressures than R410A, but still requires proper handling.

The R22 Pressure-Temperature Relationship

For R22, the saturation pressure rises exponentially with temperature.

Approximate formula (Antoine equation):

log10(P) = A – (B / (T + C))

But it is easier to use the calculator or a PT chart.

Key points:

• 0°F saturation → about 20 psig
• 20°F saturation → about 36 psig
• 32°F saturation → about 52 psig
• 40°F saturation → about 68 psig
• 45°F saturation → about 76 psig
• 50°F saturation → about 84 psig
• 100°F saturation → about 196 psig
• 120°F saturation → about 273 psig

LIVE R22 PT Chart Calculator

Enter either pressure or temperature. The calculator finds the other value instantly.

❄️ R22 PT Chart Calculator

Find saturation temperature from pressure or vice versa

🔧 Pressure (psig)

Gauge pressure (psig)

⇄

🌡️ Temperature (°F)

Saturation temperature

📊 PRESSURE-TEMPERATURE METER

0 psig / 0°F

💡 R22 saturation: 76 psig = 45°F. Typical evaporator pressure: 60-80 psig (35-45°F).

⚡ R22 is being phased out. For existing systems, use reclaimed refrigerant only.

How to Use This R22 PT Chart Calculator

It is very simple.

To find saturation temperature: Type the pressure in psig. The calculator shows the corresponding saturation temperature.

To find saturation pressure: Type the temperature in °F. The calculator shows the corresponding pressure.

To swap values: Click the swap button (⇄) between the boxes.

R22 PT Chart (Quick Reference)

R22 Operating Pressures

Superheat Calculation with R22

Superheat is the difference between actual suction line temperature and saturation temperature.

Superheat = Suction Line Temp – Saturation Temp

Example: Suction pressure = 72 psig → saturation = 45°F. Suction line temp = 55°F.

Superheat = 55 – 45 = 10°F (good range for TXV systems).

Target superheat: 10-15°F for fixed orifice. 8-12°F for TXV.

Subcooling Calculation with R22

Subcooling is the difference between saturation temperature and actual liquid line temperature.

Subcooling = Saturation Temp – Liquid Line Temp

Example: Liquid pressure = 230 psig → saturation = 120°F. Liquid line temp = 105°F.

Subcooling = 120 – 105 = 15°F (good range: 8-15°F).

Real Examples: Different Scenarios

Example 1: Normal AC operation

• Suction pressure: 72 psig → 45°F saturation
• Suction line temp: 55°F → Superheat = 10°F
• Liquid pressure: 200 psig → 105°F saturation
• Liquid line temp: 90°F → Subcooling = 15°F

Result: Properly charged system.

Example 2: Low refrigerant charge

• Suction pressure: 55 psig → 35°F saturation
• Suction line temp: 60°F → Superheat = 25°F (too high)
• Liquid pressure: 160 psig → 90°F saturation
• Liquid line temp: 85°F → Subcooling = 5°F (too low)

Result: Add refrigerant.

Example 3: Overcharged system

• Suction pressure: 85 psig → 52°F saturation
• Suction line temp: 55°F → Superheat = 3°F (too low)
• Liquid pressure: 250 psig → 125°F saturation
• Liquid line temp: 105°F → Subcooling = 20°F (too high)

Result: Remove refrigerant.

Example 4: Restriction (clogged filter drier)

• Suction pressure: 45 psig → 28°F saturation
• Suction line temp: 50°F → Superheat = 22°F
• Liquid pressure: 260 psig → 130°F saturation
• Liquid line temp: 100°F → Subcooling = 30°F

Result: Check for restriction.

R22 vs. R410A Pressures

R22 pressures are about 40-45% lower than R410A.

R22 Phase-Out Information

Production phase-out schedule:

• 2010: No new R22 equipment manufactured
• 2015: 90% reduction in production
• 2020: Complete phase-out of new R22 production

What this means:

• New R22 cannot be manufactured
• Only reclaimed, recycled, or recovered R22 can be used
• Prices have increased significantly
• Consider retrofitting to R407C, R422B, or R438A

Drop-in replacements:

Retrofitting R22 Systems

Step 1: Recover existing R22
Step 2: Replace filter-drier
Step 3: Change oil if needed (POE for R407C)
Step 4: Pressure test with nitrogen
Step 5: Evacuate to 500 microns
Step 6: Charge with replacement refrigerant
Step 7: Adjust TXV or charge for proper superheat/subcooling

Safety Notes for R22

• Pressure: R22 operates at lower pressures than R410A. Standard gauges work.
• Ozone depletion: Never vent R22. Recover properly.
• Oil compatibility: R22 uses mineral oil. Most replacements use POE or alkylbenzene.
• Leak detection: Use electronic leak detectors rated for HCFCs.

Frequently Asked Questions (FAQs)

1. What is the normal suction pressure for R22?

60-80 psig depending on indoor load and outdoor temperature.

2. What is the normal head pressure for R22?

180-250 psig depending on outdoor temperature.

3. What is the saturation temperature at 76 psig?

About 45°F.

4. What is the saturation pressure at 100°F?

About 196 psig.

5. Is R22 still available?

Only reclaimed, recycled, or recovered R22. Production of new R22 stopped in 2020.

6. Can I mix R22 with R410A?

No. Never mix refrigerants. They are incompatible.

7. How do I calculate superheat with R22?

Superheat = Suction line temp – Saturation temp (from PT chart).

8. How do I calculate subcooling with R22?

Subcooling = Saturation temp – Liquid line temp.

9. What is the target subcooling for R22?

8-15°F for TXV systems.

10. What is a good replacement for R22?

R407C, R422B, and R438A are common replacements. Check with your equipment manufacturer.

Common Mistakes

Mistake #1: Using R410A PT chart for R22

R22 pressures are much lower. Use the correct chart.

Mistake #2: Not converting gauge pressure to absolute

For PT relationships, use gauge pressure. The calculator uses psig.

Mistake #3: Adding R22 to a system with a leak

Fixing the leak is required by EPA regulations. Do not just top off.

Mistake #4: Confusing superheat with subcooling

Superheat is suction line. Subcooling is liquid line.

Mistake #5: Using R22 in a system designed for R410A

Pressures are different. Components are not compatible.

Final Thoughts

R22 systems are still out there. They need proper service.

My R22 PT Chart Calculator gives you:

• Saturation temperature from pressure
• Saturation pressure from temperature
• Pressure-temperature meter
• Troubleshooting guidance

Bookmark this page. Use it for charging, troubleshooting, and maintenance of R22 systems.

The next time you need to check R22 pressures, you will have the PT relationship at your fingertips.

Disclaimer: This is an educational tool. Always follow EPA regulations for refrigerant handling and recovery.

External Links (Authority Backlinks):

1. Wikipedia – Chlorodifluoromethane{:target=”_blank” rel=”noopener noreferrer”}
2. Wikipedia – Refrigerant{:target=”_blank” rel=”noopener noreferrer”}
3. Wikipedia – Montreal Protocol{:target=”_blank” rel=”noopener noreferrer”}

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