Pressure Gauge, Tests And Measurements: Notes
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Pressure gauge display
- Temperature scale for refrigerant R134a CF3-CH2F or CH2F-CF3.
- Pressure scale
NOTE:
Pressure is measured in different units: 1 MPa (mega Pascal) corresponds to 10 bar (145.04 psi) positive pressure or 145 psi. 1 bar (14.5 psi) absolute pressure corresponds to 0 bar (0 psi) positive pressure and thus to the ambient pressure (atmospheric pressure).
The pressure gauge may have one or more temperature scales in addition to the pressure scale. The R134a scale values are assigned according to the vapor pressure table. Since various refrigerants create different vapor pressures at the same temperature, each temperature scale is identified for the respective refrigerant.