The correct suction pressure for a freezer using R-134a (1,1,1,2-tetrafluoroethane) as the refrigerant can vary depending on several factors, such as the freezer's temperature settings, design, size, and load conditions. However, I can provide you with some general guidelines.
For a typical medium-temperature freezer using R-134a, the suction pressure at the compressor inlet should be around 5 to 10 psi (pounds per square inch) when the freezer is operating and at its steady-state condition. This pressure corresponds to a temperature of approximately -10 to -20 degrees Fahrenheit (-23 to -29 degrees Celsius).
It's crucial to note that these values are just rough estimates and should not be taken as a definitive recommendation for your specific freezer. The actual suction pressure requirement for your freezer should be determined by referring to the manufacturer's specifications and guidelines.
For any refrigeration system, including freezers, it's best to have the equipment serviced and maintained by a qualified HVAC (Heating, Ventilation, and Air Conditioning) technician or a professional refrigeration technician. They can accurately measure and adjust the suction pressure and ensure the system is operating within its intended specifications for optimal performance and efficiency.