Which PT Chart Do I Need? A Refrigerant Routing Table
Chart data computed on ; next check .
At a glance
A one-line-per-refrigerant table routing R-454B, R-32, R-410A, R-22 and R-134a to their charts, noting which are blends with glide and which have a single saturation curve, and that superheat always reads from the dew point, subcooling from the bubble point.
On this page
This site has five pressure–temperature charts and one calculator that reads them for you. If you already know which refrigerant you're working with, the table below gets you to the right page in one line; the notes after it explain the two columns that decide the answer.
Route by refrigerant
| Refrigerant | Often found in | Blend or single | Glide | Superheat / subcooling |
|---|---|---|---|---|
| R-454B | Newer, lower-GWP systems sold as an R-410A replacement | Blend | A few degrees | Dew point for superheat, bubble point for subcooling |
| R-32 | Newer split systems and mini-splits | Single component | None | One curve for both |
| R-410A | Most residential air conditioners and heat pumps of the last two decades | Blend | A few tenths of a degree | Dew point for superheat, bubble point for subcooling |
| R-22 | Older residential systems, largely being phased out | Single component | None | One curve for both |
| R-134a | Automotive air conditioning and some refrigeration equipment | Single component | None | One curve for both |
For working superheat and subcooling instead of just looking up one number, the superheat and subcooling calculator covers all five refrigerants in one place.
Reading glide
Glide is the gap, at one pressure, between a blend's bubble point (where its liquid first starts to boil) and its dew point (where the last of the liquid has turned to vapor). R-454B and R-410A carry it, because CoolProp models each as a mixture with two components boiling at different points. R-32, R-22 and R-134a don't: each is a single compound, so it boils and condenses at one temperature for any given pressure, and its chart needs only one column.
Superheat and subcooling, one rule for all five
Whichever refrigerant you're reading, the suction side is checked against the higher-temperature saturation point and the liquid side against the lower one. On a blend that means dew for the suction line and bubble for the liquid line; on a single-component refrigerant both lines land on the same curve, so there's no choice to make. The calculator above applies that rule for whichever refrigerant is selected, instead of asking you to remember which point goes with which line.
Why five separate charts, not one
Saturation pressure is chemical, not universal: a given pressure means a different temperature for every fluid, and a blend's bubble and dew points move independently of a single-component refrigerant's one curve. That's why this site runs one page per refrigerant rather than a combined table — each page's own chart and worked example match that refrigerant's own numbers, not an average of several.