Periodic Clean Water Rinse
A monthly clean water rinse is recommended for coils that are applied in coastal or industrial environments to help to remove chlorides, dirt and debris. An elevated water temperature (not to exceed 130ºF) will reduce surface tension, increasing the ability to remove chlorides and dirt. Pressure washer PSI must not exceed 900 psig and the nozzel should remain at leat 1 foot from the coil to avoid damaging fin edges.
Source: Daikin (oslo.daikinapplied.com)