Testing Boat Air Conditioning Before Purchase
The short answer
Run it for a full hour, not five minutes. Check the overboard discharge, measure the air at every grille, look in the bilge for fresh water, find the strainer and see whether it is reachable, and ask for service records. An hour is long enough for a marginal system to reveal itself.
Testing Boat Air Conditioning Before Purchase — Requirements and Limitations
An unreachable strainer tells you more than any record does. A strainer behind a panel that needs tools is a strainer that has not been cleaned, and everything downstream of it will show that in time.
Fresh water in the bilge is the other reliable tell: it means the condensate was plumbed there from new, which is a shortcut somebody took and a job you will inherit.
This is an operating demonstration for a prospective buyer, not a technical survey. The pre-purchase survey checklist covers installation and records. Ask a specialist to assess condition, safety and remaining service needs before relying on the system in the purchase decision.
Steps for Testing Boat Air Conditioning Before Purchase
- Start it and time an hour — many faults only appear once the system is up to temperature.
- Confirm a steady warm trickle at the overboard discharge.
- Measure or feel the air at every grille; compare cabins against each other.
- Look in the bilge for fresh water, which means the condensate drains there.
- Find the strainer and the seacock: if you cannot reach them, nobody has been servicing them.
- Ask for service records and the unit's age — ten to fifteen years is a typical life.
- Listen for vibration through the hull, which points at perished mounts.
Related Sizing, Installation and Service Guides
Each of these answers a different part of the same problem.
- the full survey checklistwritten for exactly this
- what bilge water meansthe fault you would be buying
- if it is near the endrepair against replacement, costed
- how long they lastto place the unit's age