Digital Refrigerant Pressure-Temperature Chart
Interactive refrigerant Pressure-Temperature (PT) chart for R-454B, R-32, R-410A, R-22, and zeotropic blends. Instant bubble and dew point saturation lookups.
Interactive Calculator & Visualizer
📊 Complete R-454B Pressure-Temperature Table
High-precision saturation property reference data across standard operating temperatures. Click any row to load into gauge.For zeotropic blends such as R-454B (~1.5°F glide), evaluate Subcooling using the Bubble Point (liquid line) and Superheat using the Dew Point (suction line) to account for phase-change temperature glide during field charging diagnostics. Read the A2L Refrigerant Transition & Field Diagnostics Guide →
| Temp (°F) | Temp (°C) | Saturation Pressure (PSIG) | Metric (Bar) | Bubble Temp (°F) | Glide (°F) | Typical Operating Zone |
|---|---|---|---|---|---|---|
| -20°F | -28.9°C | 20.3 PSIG | 2.41 bar | -21.4 | 1.4 | Heat Pump Evaporator |
| -15°F | -26.1°C | 24.4 PSIG | 2.7 bar | -16.5 | 1.5 | Heat Pump Evaporator |
| -10°F | -23.3°C | 28.6 PSIG | 2.99 bar | -11.5 | 1.5 | Heat Pump Evaporator |
| -5°F | -20.6°C | 33.4 PSIG | 3.32 bar | -6.5 | 1.5 | Heat Pump Evaporator |
| 0°F | -17.8°C | 38.6 PSIG | 3.67 bar | -1.5 | 1.5 | Heat Pump Evaporator |
| 5°F | -15°C | 44.5 PSIG | 4.08 bar | 3.5 | 1.5 | Heat Pump Evaporator |
| 10°F | -12.2°C | 50.7 PSIG | 4.51 bar | 8.5 | 1.5 | Heat Pump Evaporator |
| 15°F | -9.4°C | 57.7 PSIG | 4.99 bar | 13.5 | 1.5 | Heat Pump Evaporator |
| 20°F | -6.7°C | 65.4 PSIG | 5.52 bar | 18.5 | 1.5 | Heat Pump Evaporator |
| 25°F | -3.9°C | 73.6 PSIG | 6.09 bar | 23.5 | 1.5 | Heat Pump Evaporator |
| 30°F | -1.1°C | 82.5 PSIG | 6.7 bar | 28.5 | 1.5 | AC Evaporator (Low Side) |
| 35°F | 1.7°C | 93.3 PSIG | 7.45 bar | 33.5 | 1.5 | AC Evaporator (Low Side) |
| 40°F | 4.4°C | 112 PSIG | 8.74 bar | 38.5 | 1.5 | AC Evaporator (Low Side) |
| 45°F | 7.2°C | 125.6 PSIG | 9.67 bar | 43.5 | 1.5 | AC Evaporator (Low Side) |
| 50°F | 10°C | 137.5 PSIG | 10.49 bar | 48.5 | 1.5 | AC Evaporator (Low Side) |
| 55°F | 12.8°C | 150.5 PSIG | 11.39 bar | 53.5 | 1.5 | AC Evaporator (Low Side) |
| 60°F | 15.6°C | 164.4 PSIG | 12.35 bar | 58.5 | 1.5 | Condenser (High Side) |
| 65°F | 18.3°C | 179.1 PSIG | 13.36 bar | 63.5 | 1.5 | Condenser (High Side) |
| 70°F | 21.1°C | 195.2 PSIG | 14.47 bar | 68.5 | 1.5 | Condenser (High Side) |
| 75°F | 23.9°C | 212.2 PSIG | 15.64 bar | 73.5 | 1.5 | Condenser (High Side) |
| 80°F | 26.7°C | 229.9 PSIG | 16.86 bar | 78.5 | 1.5 | Condenser (High Side) |
| 85°F | 29.4°C | 248.9 PSIG | 18.17 bar | 83.5 | 1.5 | Condenser (High Side) |
| 90°F | 32.2°C | 269 PSIG | 19.56 bar | 88.5 | 1.5 | Condenser (High Side) |
| 95°F | 35°C | 290.1 PSIG | 21.01 bar | 93.5 | 1.5 | Condenser (High Side) |
| 100°F | 37.8°C | 311.3 PSIG | 22.48 bar | 98.5 | 1.5 | Condenser (High Side) |
| 105°F | 40.6°C | 332.1 PSIG | 23.91 bar | 103.5 | 1.5 | Condenser (High Side) |
| 110°F | 43.3°C | 354.7 PSIG | 25.47 bar | 108.5 | 1.5 | Condenser (High Side) |
| 115°F | 46.1°C | 378.4 PSIG | 27.1 bar | 113.5 | 1.5 | Condenser (High Side) |
| 120°F | 48.9°C | 403.1 PSIG | 28.81 bar | 118.5 | 1.5 | Condenser (High Side) |
| 125°F | 51.7°C | 428.7 PSIG | 30.57 bar | 123.5 | 1.5 | Condenser (High Side) |
| 130°F | 54.4°C | 455.7 PSIG | 32.43 bar | 128.5 | 1.5 | Condenser (High Side) |
Engineering Methodology & Governing Equations
Vapor-Compression Refrigeration Thermodynamic Cycle
Closed-loop thermodynamic phase change between high-side liquid condensation and low-side vapor expansion.
PT Calculation Methodology & Refrigerant Property Data
A Pressure-Temperature (PT) chart defines the thermodynamic saturation curve of a refrigerant. In practical HVAC/R service, saturation pressure indicates the exact temperature at which the refrigerant boils in the evaporator coil or condenses in the condenser coil. When servicing modern low-GWP A2L systems (such as R-454B and R-32) alongside legacy R-410A and R-22 units, selecting the correct saturation curve is essential for accurate diagnostics.
- Classify Pure vs. Zeotropic Refrigerants: Pure single-component substances (such as R-32, R-22, and R-134a) and near-azeotropic mixtures (such as R-410A) evaporate and condense at a constant temperature along a single saturation curve. In contrast, zeotropic blends (such as R-454B and R-407C) exhibit temperature glide, requiring separate dew and bubble curves.
- Use the Dew Point Curve for Superheat: When measuring low-side suction pressure at the evaporator outlet, reference the Dew Point (Vapor Saturation) curve to determine the true vapor saturation temperature (T_sat_dew). Cross-reference actual measurements using the Target Superheat & Subcooling Calculator.
- Use the Bubble Point Curve for Subcooling: When measuring high-side liquid line pressure before the expansion device (TXV/EEV), reference the Bubble Point (Liquid Saturation) curve to determine the true liquid saturation temperature (T_sat_bubble).
- Convert Between Gauge and Absolute Pressure: Manifold gauges measure gauge pressure (PSIG). Thermodynamic property equations utilize absolute pressure (PSIA), calculated at standard sea-level barometric pressure as PSIA = PSIG + 14.696.
Refrigerant Saturation vs. Air-Side Psychrometric Dew Point
In direct-expansion (DX) cooling systems, evaporator heat transfer connects refrigerant-side phase equilibrium with air-side psychrometrics:
- Latent Dehumidification Threshold: Dehumidification begins only when the evaporator coil surface temperature (governed by refrigerant saturation temperature T_sat_dew) is lower than the entering moist-air dew point (T_dp). Determine entering air dew point using the Psychrometric Calculator.
- Sensible-Only Cooling: If T_sat_dew remains above the entering air dew point (T_sat_dew > T_dp), no moisture condenses on coil fins; the process is purely sensible cooling along a constant humidity ratio line (W).
- Coil Freeze Hazard (32°F Boundary): When suction pressure drops such that T_sat_dew < 32.0°F (0°C), condensed moisture freezes into frost and ice on coil fins, starving airflow and risking liquid slugging to the compressor.
Refrigerant Saturation Property Mapping & Vapor-Liquid Equilibrium
| Symbol | Variable | Description | Standard Units |
|---|---|---|---|
P_{\text{sat}} | Saturation Pressure | Equilibrium vapor pressure where liquid and gas coexist in phase change | PSIA, PSIG, or Bar |
T_{\text{sat}} | Saturation Temperature | Boiling or condensing temperature corresponding to the measured manifold pressure | °F or °C |
\text{Glide} | Zeotropic Temperature Glide | Temperature difference between bubble point (100% liquid) and dew point (100% vapor) at constant pressure | °F |
\text{PSIG} | Gauge Pressure | Pressure relative to local atmospheric pressure (0 PSIG = 14.696 PSIA at standard sea level) | PSIG |
Supporting Research & Technical References
• Low-GWP A2L Transition: A2L Refrigerant Transition & Charge Limit Sizing Guide — ASHRAE 15-2024 charge calculations and UL 60335-2-40 mitigation tiers.
• Open Benchmark Dataset: A2L Refrigerant Flammability & Glide Benchmark (200 Vectors) — downloadable CSV with deterministic state vectors.
• Air-Side Psychrometrics: Moist Air Psychrometric Calculator — calculate moist-air dew point, wet bulb, and specific enthalpy across barometric elevations.
• Field Charging Diagnostics: Target Superheat & Subcooling Calculator — evaluate target superheat for fixed orifices and subcooling benchmarks for TXVs per ACCA field procedures.
• Applied Research: Thermodynamic Modeling of Zeotropic A2L Refrigerant Glide (Report HL-TR-2026-A2L05) — phase equilibrium derivations and saturation equations.
• Field Handling & Tooling Protocols: R-454B vs. R-32 Field Service & Recovery Protocols (Report HL-TR-2026-A2L02) — DOT 4BA cylinder recovery limits, spark-proof tool certification, and vacuum decay diagnostics.
Standard Engineering Reference Matrix
Refrigerant Saturation & Pressure-Temperature Benchmark Table
Operating saturation pressures across standard residential cooling design benchmarks (40°F Evaporator Suction / 110°F Condenser Liquid):
| Refrigerant | ASHRAE Safety Class | GWP Rating | 40°F Evaporator (Suction) | 110°F Condenser (Liquid) | Temperature Glide |
|---|---|---|---|---|---|
| R-454B | A2L (Lower Flammability) | 466 | 112.0 PSIG (Dew) | 361.8 PSIG (Bubble) | 1.5°F |
| R-32 | A2L (Lower Flammability) | 675 | 119.0 PSIG | 371.0 PSIG | 0.0°F (Pure) |
| R-410A | A1 (Non-Flammable) | 2,088 | 118.0 PSIG | 365.0 PSIG | 0.2°F (Near-Azeotrope) |
| R-22 | A1 (Non-Flammable) | 1,810 | 68.5 PSIG | 226.0 PSIG | 0.0°F (Pure) |
| R-134a | A1 (Non-Flammable) | 1,430 | 35.0 PSIG | 146.4 PSIG | 0.0°F (Pure) |
| R-404A | A1 (Commercial Low-Temp) | 3,922 | 86.5 PSIG | 273.5 PSIG | 0.9°F |
| R-407C | A1 (R-22 Retrofit) | 1,774 | 63.5 PSIG (Dew) | 262.0 PSIG (Bubble) | 10.0°F (High Glide) |
Worked Engineering Sizing Example
Worked Example 1: Verifying Suction Superheat on an R-454B Heat Pump
Scenario: A technician is commissioning an R-454B residential split heat pump in cooling mode. The digital manifold connected to the true suction service port reads 118.0 PSIG, and a pipe-clamp thermocouple on the suction vapor line reads 53.5°F.
Step 1: Select the Dew Point Saturation Curve
Because suction line superheat represents vapor state leaving the evaporator, evaluate the Dew Point curve for zeotropic R-454B.
Step 2: Determine Vapor Saturation Temperature (T_sat_dew)
At 118.0 PSIG R-454B: T_sat_dew = 41.5°F
Step 3: Calculate Actual Suction Superheat
Actual Superheat = T_line - T_sat_dew = 53.5°F - 41.5°F = 12.0°F Superheat
✓ Diagnostic Result: 12.0°F superheat verifies that the evaporator coil is operating with full active boiling surface while protecting the compressor from liquid slugging. Cross-check against target superheat using the Superheat & Subcooling Calculator.
Worked Example 2: Verifying Liquid Line Subcooling on an R-454B System
Scenario: The same technician measures high-side liquid line pressure at 361.8 PSIG before the thermal expansion valve (TXV), with a pipe-clamp temperature of 100.0°F.
Step 1: Select the Bubble Point Saturation Curve
Because liquid line subcooling measures 100% condensed liquid leaving the condenser, evaluate the Bubble Point curve for R-454B.
Step 2: Determine Liquid Saturation Temperature (T_sat_bubble)
At 361.8 PSIG R-454B: T_sat_bubble = 110.0°F
Step 3: Calculate Actual Liquid Subcooling
Actual Subcooling = T_sat_bubble - T_line = 110.0°F - 100.0°F = 10.0°F Subcooling
✓ Diagnostic Result: 10.0°F subcooling ensures a solid column of liquid enters the expansion valve without premature flash-gas formation.
Frequently Asked Questions
What is the boiling point of R-454B at atmospheric pressure?
What is temperature glide in zeotropic refrigerants like R-454B and R-407C?
What is the typical operating pressure for R-454B on high and low sides?
Governing Research Monograph: Thermodynamic Phase-Equilibrium and Non-Linear Temperature Glide Modeling of Next-Generation Zeotropic A2L Refrigerants (R-454B & R-32)
Report: HL-TR-2026-A2L05 • DOI: 10.7910/DVN/SR1NZO • Authors: HVACLogic Research Group, Miad S.
Calculation engines undergo software-level verification against documented equations, reference values, boundary conditions, and automated tests referencing ASHRAE, ACCA, SMACNA, and NIST publications.
⚖️ Engineering Reference & Regulatory Disclaimers
Engineering Reference Notice: HVACLogic.org is an independent computational reference and engineering design aid authored by Miad S. Calculations are based on consensus engineering formulations (including ASHRAE, ACCA, and SMACNA publications) and are intended solely for preliminary estimation, parametric analysis, and educational use. HVACLogic does not provide licensed professional engineering services, structural evaluations, or legally binding code determinations.
Professional Review & Permitting Notice: Where the applicable jurisdiction, project type, occupancy classification, permit process, or professional-practice law requires licensed professional review, certification, or a sealed/stamped calculation, the user must obtain that review from an appropriately licensed Professional Engineer (PE) or qualified mechanical contractor. Where a jurisdiction or Authority Having Jurisdiction (AHJ) requires specific calculation software, documentation, or permit submittal forms, users must follow the applicable local requirements.
- Manufacturer installation, operation, and service instructions;
- Applicable refrigerant safety standards (ANSI/ASHRAE 15, ASHRAE 34, and UL 60335-2-40);
- Required technician EPA Section 608 certifications and trade qualifications;
- Applicable mechanical code, fuel gas code (NFPA 54/IFGC), and local Authority Having Jurisdiction (AHJ) requirements; or
- Equipment-specific charging, pressure testing, evacuation, and ventilation procedures.
Manufacturer Data Notice: Generic engineering formulas provide baseline theoretical approximations. Actual equipment performance, expanded cooling/heating capacities at specific outdoor temperatures, sensible-to-total heat ratios, fan airflow curves, and electrical characteristics (MCA/MOP) must be verified against manufacturer technical product data specifications.