Correct amounts of refrigerant are essential to proper operation of air conditioning equipment (refrigeration too). One sign that a system is low is the evaporator coils (the device which chills the air) will become coated with ice. This reduces air flow and cooling and can lead to compressor damage.

Last year we had one of our four Marine Air units exhibit this symptom on our way to Panama. But once we were in a more normal environment it seemed OK, so we did not bother to service the unit.

We’re thinking now about warmer climates, so had a tech onboard to check the units. As expected, the one unit was low on gas. The other three are fine.

If you don’t have refrigeration gauges aboard you can get an indication of correct operation from the temperature of the suction and pressure piping. Ideally there will be a record of these temperatures with a remote sensing heat gun. Note air and water temperature as well.