Originally Posted by
nike123
To correctly charge a capillary or metering piston system, you must put in enough refrigerant to cool the
compressor, but never so much that it allows floodback under any operating conditions. So to charge using the superheat method, you must consider:
- Outdoor temperature
- Evaporator temperature: which reflects airflow, system conditions, indoor humidity and temperature.
- Suction line temperature: which reflects superheat.
- Condenser efficiency
For that purpose some manufacturers has developed charging charts.
If they are not available for your case than you should simulate borderline conditions and adjust charge accordingly.
Sticking to fixed superheat value could result with broken compressor depending on conditions when charged.
Best method for capillary/orifice is to charge by weight.