Color WHITE - range 0-25 PSI: too low pressure in the system. The refrigerant needs to be topped up.
GREEN - range 25-55 PSI: correct, preferred system pressure. System filled correctly (see chart below).
RED - above 55 PSI: too high system pressure. It should be reduced to the proper level.
Pressure and ambient temperature:
The correct air conditioning system pressure indicated by the pressure gauge will vary depending on the ambient temperature:
TEMPERATURE - PRESSURE:
- 18°C - 25-35 PSI
- 21°C - 35-40 PSI
- 24°C - 35-45 PSI
- 27°C - 40-50 PSI
- 29°C - 45-55 PSI
- 32°C - 45-55 PSI
- 35°C - 50-55 PSI
- 38°C - 50-55 PSI
- 41°C - 55 PSI
- 43°C - 55 PSI
The system can also be charged below18°C, but in this case the pressure gauge will show a pressure below25 PSI.
