Marine Air Conditioning Filter and Duct Cleaning
Restricted airflow makes a correctly sized unit behave like an undersized one, and the return-air filter is the usual culprit.
Marine Air Conditioning Filter and Duct Cleaning: Schedule and Equipment
The return air path is where most airflow problems live. A furred filter or a grille blocked by stowage will drop capacity noticeably, and the symptom looks exactly like a refrigeration fault.
Marine Air Conditioning Filter and Duct Cleaning: Procedure
If you skip it: The unit runs longer, dehumidifies less, and gets blamed for being too small.
Record the date, what you found and any parts used in the boat's maintenance log. A repeat change—less water flow, faster fouling, a new smell or a breaker that trips again—is often more useful to a technician than a one-off reading. Check the current manual and official sources before changing the procedure, and stop at the licensed-work boundary described in the disclaimer.