What could cause high discharge pressure in a refrigeration system?

High discharge pressure in a refrigeration system may be caused by the presence of non-condensables. Non-condensables are substances that do not change into a liquid phase at the operating temperatures and pressures within the system, such as air or other gases. When these substances are present in the refrigeration system, they can occupy space within the condenser, reducing the system’s ability to effectively condense the refrigerant vapor into a liquid. This reduces the overall efficiency of the system and leads to an increase in the discharge pressure as the compressor has to work harder to compress the refrigerant mixture that includes the non-condensables.

In a properly functioning refrigeration system, the refrigerant should be fully condensed, resulting in a predictable discharge pressure that corresponds to the refrigerant's saturation temperature. The introduction of non-condensables disrupts this process and raises the pressure, potentially leading to overheating and increased wear on the compressor.

Understanding this helps underline the importance of ensuring that all components of the refrigeration system are free from non-condensables during operation, allowing for optimal performance.