Coastal Condo Not Cold: Condenser Fins Crusted with Salt

A flat near the coast cooling poorly in the afternoon and adequately at night. The outdoor unit sits on an exposed ledge facing the water. Its coil is visibly crusted and the fins are discoloured in places.

A crusted coil invites a rinse, and that is the right first step, but it answers only half the question. Deposit sitting on the surface restricts airflow and comes away with water. Corrosion under it has removed metal, and where fin material has gone the coil will never transfer heat as it once did. Looking closely at the fins after the rinse is what separates a unit that has been cleaned from one that has been damaged.

Air carrying salt deposits a crust that blocks airflow and holds moisture against the metal underneath. The crust is the reversible part. The moisture it traps drives corrosion into the aluminium fins and the joints behind them, which is not reversible and continues under every subsequent deposit. A coastal unit therefore accumulates two problems at once, and only one of them responds to cleaning.

The coil is rinsed thoroughly, which restores most of what was lost, and the corroded areas are assessed honestly for what remains. Where corrosion is early, protective treatment slows what follows. Where fin material has gone, capacity does not fully return and the useful thing is to know that now rather than after a second visit produces the same result.