Air Conditioning systems that are installed on boats and yachts are very different from the typical residential and commercial air conditioning units that most land-based HVAC contractors install and service… so it makes sense that qualified MARINE air conditioning experts that specialize in boat & yacht HVAC systems are your best choice for installing maintaining, and repairing marine HVAC systems.

Here are just a few key reasons why you should call a qualified marine HVAC specialist for all your air conditioning and refrigeration needs.

Reason #1 – Yacht and Marine HVAC systems are seawater cooled (not air-cooled) so proper seawater flow through these systems is absolutely critical in order for marine systems to operate properly.

Above: These HVAC sea water pumps were properly installed by Yacht-HQ. They are securely mounted below the water line and hoses slope upwards so that air cannot get trapped in the pump housing. All hoses are properly double-clamped and all threaded fittings are assembled with PFTE tape to prevent leaks.

• Seawater cooling sub-systems require care and maintenance to periodically remove marine growth and mineral deposits that frequently clog seawater pumps, strainers, and hoses.
• Pumps and plumbing must be designed and installed properly in order to reliably deliver the desired flow of cooling water. Too much flow causes increased erosion & corrosion of metallic components such as heat exchangers. Too little flow results in poor performance and/or “high pressure” faults which are indicated by “HPF”, “HI PS”, or “E1” errors on digital HVAC control panels.
• Hose clamps, sea strainers, seacocks, and through hull fittings must be inspected, maintained, and replaced with appropriate marine-grade parts on an as-needed basis. Failure to exercise seacocks or replace rusty hose clamps is an invitation for disaster.

Reason #2 – On-board HVAC systems are often installed in hard-to-reach areas so they aren’t exactly easy to access for routine maintenance. Therefore, they don’t often get the preventative care and attention that is needed to keep minor issues from becoming bigger problems.

Above: This Webasto FCF self-contained unit was installed on an Island Packet 38 by an unknown contractor or by a “DIY” owner. Either way, this installation makes it painful and time-consuming just to clean the air filter (which really should be done at least every three months). We call this type of installation “maintenance proof” because it is so difficult to access.

• Condensation catch pans should all have drain lines to efficiently route water to a bilge or sump area. A clogged (or non-existent) drain line can cause thousands of dollars of damage from mold, mildew, rot, or rust/corrosion.
• Air filters must be cleaned/changed frequently to ensure proper air flow through the system and to maintain acceptable indoor air quality.
• Refrigerant lines MUST be properly insulated in order to prevent condensation from forming and dripping onto surfaces where mold, mildew, and rot can cause damage.

Reason #3 – Modern yacht air conditioning systems have sophisticated control systems that should be setup and configured and NOT simply left with the “default” settings.

Above: This MicroAir Digital Control Board is popular with numerous HVAC system manufacturers because it offers a number of configurable options at a reasonable cost.

• The blower/fan for your air conditioner should be configured to be “always on” in order to keep air moving throughout your boat. Failure to do this leads to inconsistent system performance and allows increased humidity which can encourage mold & mildew. This setting is typically NOT enabled by default.
• Thermostats must be calibrated in order to display accurate temperature readings. Most thermostats are NOT properly calibrated by default.

Reason #4 – Most marine systems are equipped with dehumidification, reverse cycle (heat pump), and/or electric heating capabilities. Knowing how (and when) to use these options can significantly reduce your utility and maintenance costs.

Above: Even “simple” electronic control boxes have configurable controls, such as a lock-out timer for the compressor (to prevent short-cycling).

• Most systems have a “dehumidify” mode that can be accessed via the digital control panel. Using this mode when you are away from the boat will dramatically reduce electric bills and minimizes marine growth in the seawater cooling system while providing necessary dehumidification to keep mold and mildew from growing inside the boat.
• Most marine HVAC systems have delicate “reversing valves” that are used to automatically switch-over from cooling to heating mode. These valves MUST be exercised regularly in order to prevent them from locking-up. For this reason, Yacht-HQ recommends leaving HVAC systems in an “Auto” mode (and setting an appropriate temperature on the thermostat) which allows the HVAC system to automatically switch back-and-forth between heating and cooling modes as needed. Simply setting the system in cooling mode (and leaving it there) will, over time, allow the reversing valve to get “stuck” in the cooling mode which makes heating mode inoperable. This is an expensive part to replace.

Reason #5 – Boats and yachts live in a hostile (hot, damp, and salty) environment in which corrosion wrecks havoc on wiring, metals, electrical components, and electronics.

Above: This HVAC System Control Board failed catastrophically moments after it was sprayed with salt water from a ruptured sea water hose.

• Yacht-HQ uses ONLY marine-grade tinned stranded copper wiring and adhesive heat shrink wire terminals for AC (120/240 volt) and DC (12/24/32/48 volt) wiring. Untinned wire, solid (not stranded) conductors, aluminum wire, and the nylon (plastic) wire terminals found at hardware and home improvement stores are NOT acceptable in a marine environment. Failure to use the proper materials WILL lead to premature systems failure as corrosion and/or short circuits frequently cause irreparable damage to electrical components and electronic controls.
• Is should be obvious to all that circuit boards DO NOT like to be WET and/or HOT… so HVAC control boxes should ALWAYS be mounted far away from potential sources of water and heat… even if doing so means that wiring must be extended. Wire is cheap. Circuit boards are expensive. Yacht-HQ is constantly amazed by the frequency with which we are called to replace circuit boards that failed prematurely due to water intrusion and/or over-heating.

High Quality air conditioning service isn’t necessarily expensive… but poor quality work will cost you MUCH more in the long run. Please contact Yacht-HQ for a free consultation regarding your upcoming HVAC installation, maintenance, or repair needs.