Hello Nicholas
If you are experiencing corrosion on the union connector of your refrigerator's flow meter, it is likely that there is a leak somewhere in the system. The corrosion is most likely a result of moisture getting into the area around the Union connector.
To fix this issue, you will need to first locate the source of the leak. This may involve disassembling the flow meter and inspecting the various connections and fittings. Once you have located the leak, you will need to replace the damaged component.
It is important to address this issue as soon as possible, as a leaking refrigerant system can be dangerous and can cause damage to the environment. Additionally, a leaking refrigerant system can cause the refrigerator to run less efficiently, resulting in higher energy bills and potentially shortened lifespan of the appliance.
If you are not comfortable working on refrigeration systems, it is recommended that you contact a professional technician who has the necessary knowledge and experience to diagnose and repair the issue.