Pressure-temperature data is useful because a measured pressure can be compared with the refrigerant saturation temperature. That comparison can help organize superheat, subcooling, and operating-pressure review, but it does not by itself diagnose a system, approve a charge, or verify compliance.
The ToolGrit P-T chart keeps deterministic rows for common refrigerants. Rows for R-410A, R-22, R-32, R-454B, R-407C, R-134a, R-404A, and R-290 are reconciled against archived manufacturer P-T charts (Chemours and Daikin/Weitron), and the remaining blends are flagged in-app until reconciliation. Current manufacturer product data, ASHRAE/NIST sources, SDS, equipment instructions, calibrated measurements, EPA rules, code/AHJ requirements, and qualified HVAC review control field use.
What Saturation Values Mean
A local saturation prompt can show the approximate relationship between pressure and temperature for the selected refrigerant row. For pure and near-azeotropic rows the app displays one local value. For R-407C it displays local bubble and dew prompts. For several other zeotropic rows, the app only has a single-column local prompt and explicitly flags that source gap.
For example, the R-410A row is checked against truth-library anchors around 40°F and 103 psig. That makes it useful for catching the old customer-reported low-pressure regression, but it is still not a full current manufacturer or ASHRAE table reproduction. A field measurement still needs the exact refrigerant, gauge accuracy, line-temperature method, pressure drop, stabilization, airflow/load, and equipment procedure.
Refrigerant P-T Chart
Interactive pressure-temperature saturation chart for 13 common refrigerants including R-410A, R-22, R-134a, R-454B, and R-32. Bubble/dew point for R-407C, superheat/subcooling reference.
Pure Rows, Blend Rows, and Glide
Pure refrigerants and near-azeotropic blends may be displayed as a single local saturation row. Zeotropic blends can require separate bubble and dew values. The correct reference depends on the refrigerant, current product data, equipment procedure, and the task being performed.
The app shows separate local bubble/dew prompts for R-407C because that row was retained with a two-column local split. R-454B, R-448A, and R-449A are zeotropic rows, but this app currently has only single-column local rows for them. That means manufacturer bubble/dew data must be used before superheat, subcooling, charging, or diagnostic use.
Refrigerant Rows and Review Boundaries
R-410A: The row is reconciled against manufacturer chart data with truth-library validation anchors, and carries a visible GWP-basis warning. AIM Act, replacement, retrofit, and equipment decisions remain outside the tool.
R-22: The row is retained for legacy service context. Service, recovery, recharge, sales, retrofit, and records require current EPA Section 608, manufacturer, reclaimed-refrigerant, and qualified HVAC/legal review.
R-32, R-454B, R-1234yf, and R-290: These rows carry flammability context. Listed equipment, charge limits, room volume, ventilation, leak detection, ignition-source controls, tools, labels, code/AHJ, manufacturer procedures, and qualified review control actual use.
R-744 (CO2): The row covers subcritical saturation only and is still flagged for manufacturer reconciliation. CO2 refrigeration involves high pressures and possible transcritical operation that require separate design and safety review.
Gauge Pressure, Altitude, and Measurement Quality
The app displays local atmospheric-pressure context from a standard-atmosphere formula, but it does not perform a calibrated gauge correction or replace measured station pressure. Local P-T rows are stored as psig display rows, and the altitude field is a warning prompt rather than a certified correction.
Measurement quality still matters: gauge/manifold accuracy, pressure transducer calibration, hose losses, temperature probe placement, insulation, line pressure drop, airflow, load, metering device behavior, and stabilization can all dominate the result. Use current instruments and procedures before making service decisions.