HVAC Toolkit

Pressure-Temperature Charts

Saturation P-T data for common refrigerants

Select Refrigerant

HFC / HCFC

R-22 R-32 R-125 R-134a R-143a R-404A Z R-407C Z R-410A R-507A

Low GWP (HFO)

R-449A Z R-454B Z Low GWP R-513A R-1234yf Low GWP R-1234ze(E) Low GWP

Natural

R-290 (Propane) Low GWP R-600a (Isobutane) Low GWP R-744 (CO2) Low GWP R-717 (NH3) Low GWP

Pressure Unit

psig kPa bar kgf/cm²

R-404A

Zeotropic
GWP: 3,922
ODP: 0
Temperature Glide: 0.7°C

Quick P-T Lookup

kPa

* Results are interpolated from the P-T table data

Z

Zeotropic Blend

This refrigerant has a temperature glide of 0.7°C - use the correct saturation point!

Temperature Glide Visualization

Dew Point
100% Vapor
For Superheat
0.7°C Glide
Higher Temp Lower Temp
Bubble Point
100% Liquid
For Subcooling

DEW Suction Side / Superheat

  • • Superheat = Suction Temp - Dew Point Temp
  • • Use at evaporator outlet
  • • Low pressure gauge reading
  • • Temperature where last liquid evaporates

BUBBLE Liquid Side / Subcooling

  • • Subcooling = Bubble Point Temp - Liquid Temp
  • • Use at condenser outlet
  • • High pressure gauge reading
  • • Temperature where first bubble forms

Important: Using the wrong saturation point will give incorrect superheat/subcooling readings. For R-404A with 0.7°C glide, this error can significantly affect diagnosis and charging.

Dew Point (Vapor)

Used for suction line / evaporator

°C °F kPa
-50 -58 91.0
-45 -49 132.0
-40 -40 180.0
-35 -31 235.0
-30 -22 299.0
-25 -13 372.0
-20 -4 455.0
-15 5 549.0
-10 14 655.0
-5 23 773.0
0 32 904.0
5 41 1,049.0
10 50 1,209.0
15 59 1,385.0
20 68 1,577.0
25 77 1,787.0
30 86 2,016.0
35 95 2,264.0
40 104 2,532.0
45 113 2,822.0
50 122 3,134.0

Bubble Point (Liquid)

Used for liquid line / condenser

°C °F kPa
-50 -58 86.0
-45 -49 126.0
-40 -40 174.0
-35 -31 228.0
-30 -22 290.0
-25 -13 362.0
-20 -4 443.0
-15 5 536.0
-10 14 640.0
-5 23 756.0
0 32 885.0
5 41 1,028.0
10 50 1,185.0
15 59 1,358.0
20 68 1,546.0
25 77 1,752.0
30 86 1,977.0
35 95 2,219.0
40 104 2,482.0
45 113 2,764.0
50 122 3,069.0

Pressure Units: psig = Gauge pressure (relative to atmosphere) kPa / bar / kgf/cm² = Absolute pressure