Marine Air Conditioning Care on an Unused Boat
The short answer
Flush the seawater loop with fresh water, dry the coil with the fan, clean the drip tray, shut the seacock, and leave a hatch or a vent open if the boat is secure. A shut-up boat with a damp coil is where mould starts, and the fix afterwards is much harder than the prevention.
Boat AC Care on an Unused Boat — Requirements and Limitations
Some owners leave the system running on a high set point while away, which keeps the boat dry but means paying to cool an empty boat and trusting an unattended seawater system for months. If you do, have somebody check the strainer and the bilge regularly.
The alternative — flush, dry, shut and ventilate — costs nothing and is what most owners should do. Either way, do not leave a wet coil in a closed boat.
Choose between a documented shutdown and an approved unattended operating plan. Do not isolate seawater while leaving an air conditioner enabled. The separate layup record checklist captures isolation and restart instructions; the unattended-humidity guide covers moisture inspection while away.
Related Sizing, Installation and Service Guides
Each of these answers a different part of the same problem.
- the lay-up procedurethe full version of this
- what you are preventingthe fault, and how far it can go
- if you leave it runningthe condensate question over months
- bringing it backthe bleed step that catches people