Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Refrigerant R134A Vapor Pressure Table
The vapor pressure table for every refrigerant is published in literature for the refrigeration system engineers. This table makes it possible to determine the vapor pressure acting on the column of liquid in a container if the temperature of the container is known.
Because each refrigerant has its own characteristic vapor pressure table, refrigerant can be identified by measuring the pressure and temperature.
At absolute pressure, "0 bar/psi" corresponds to absolute vacuum. Normal ambient pressure (positive pressure) equals approximately "1 bar (1.5 psi)" absolute pressure. "0 bar/psi" pressure corresponds to an absolute pressure of 1 bar (14.5 psi) on most pressure gauges (indicated by "-1 bar (-14.5 psi)" below "0 bar/psi").
Pressure is measured in different units: 1 MPa (145 psi) corresponds to 10 bar (145 psi) positive pressure. 1 bar (14.5 psi) absolute pressure corresponds to 0 bar/psi positive pressure and thus to the ambient pressure (atmospheric pressure).
| Temperature in °C (°F) | Pressure in bar (psi) of R134a |
|---|---|
| -45 (-49) | -0.61 (-8.85) |
| -40 (-40) | -0.49 (-7.11) |
| -35 (-31) | -0.34 (-4.93) |
| -30 (-22) | -0.16 (-2.32) |
| -25 (-13) | 0.06 (0.87) |
| -20 (-4) | 0.32 (4.64) |
| -15 (-5) | 0.63 (9.14) |
| -10 (14) | 1.00 (14.50) |
| -5 (23) | 1.43 (20.74) |
| 0 (32) | 1.92 (27.85) |
| 5 (41) | 2.49 (36.11) |
| 10 (50) | 3.13 (45.40) |
| 15 (59) | 3.90 (56.57) |
| 20 (68) | 4.70 (68.17) |
| 25 (77) | 5.63 (81.66) |
| 30 (86) | 6.70 (97.18) |
| 35 (95) | 7.83 (113.57) |
| 40 (104) | 9.10 (131.98) |
| 45 (113) | 10.54 (152.87) |
| 50 (122) | 12.11 (175.64) |
| 55 (131) | 13.83 (200.59) |
| 60 (140) | 15.72 (228.00) |
| 65 (149) | 17.79 (258.02) |
| 70 (158) | 20.05 (290.80) |
| 75 (167) | 22.52 (326.63) |
| 80 (176) | 25.21 (362.59) |
| 85 (185) | 28.14 (408.14) |
| 90 (194) | 31.34 (454.55) |
NO RELATED
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.