Air Conditioning: Neglecting Maintenance Can Cause Health Issues

Some yachts tend to treat the air-conditioning system as “out of sight, out of mind,” and pay little attention to maintaining the systems that process the air you breathe inside the yacht. If you neglect it, the A/C system may degrade, air quality could reduce, and there could even be health issues.

There are many types of fan-coil filters in use on board — some are custom washable and work well, but many are machine filters with a broad mesh designed to stop larger particles from being drawn into machinery. They don’t filter the microfine dust that gets sucked in, which then accumulates inside your system’s blower and ducting. Some of this dust is also coming back at you through the grills — have you wondered why a stew can clean and polish a furniture piece, removing all dust, only to return a few hours later and find a coating of dust back on the piece?

If you neglect it, the A/C system may degrade, air quality could reduce, and there could even be health issues.

Some filters in use may (because of their design) actually restrict the flow of air, creating poor performance and placing the blower under duress. On the other hand, if you can see light clearly through the filter, then particulate matter of substantial size will pass through with ease. The Goldilocks option seems to be “depth loading filter media,” which is highly effective and very inexpensive at around $4 per filter. It comes in a roll and you cut it to suit. The two-ply filter media gives a 90-day service period rather than 30 days and is becoming a popular practice on many yachts. (Remember, the white side faces out and you have to ensure the entire face of the evaporator is covered. Any more than one-quarter-inch gap or shortage, and you may as well not have a filter on it.) A marked reduction in airborne dust is achieved from the use of these filters.

A number of things are placed in or around fan coils. Most are used to control either moisture or odors and range from scent beads and strips to tea tree oil. (Be sure you aren’t masking a serious problem like mold.)

Desiccants have also become popular, but a word of caution on using products like DampRid. These desiccant beads or flakes are normally chlorides of potassium, calcium, and sodium. They’re great at reducing moisture content, but the problem arises when one of these is opened and stationed directly in front of the fan coil: While extracting moisture from the air, the desiccant bead can release very high pH vapors into the air. When this is sucked through the aluminum fins of the evaporator over a period, it causes irreversible corrosive damage to the aluminum fins and beyond. So please, don’t put it directly in front of the fan coil — or for that matter, beside or beneath electronics that are in the airflow.

This article originally ran in the September 2020 issue of Dockwalk.