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Replacing The Air Conditioning On Your Boat

Keeping Cool: AIM's Marine Group and the MyBoatWorks team embark on replacing the air-conditioning units aboard our Grand Banks 42 project boat.

There is an unwritten rule in the world of marine air conditioning that states: Air conditioning only fails when it’s needed the most. A system will purr like a kitten during your cruise along the coast of Maine but the minute you tie up to a bulkhead in St. Augustine, Florida, during a heat wave in July, that’s when trouble will hit. Lying in your berth with a bed sheet stuck to your sweating torso like a piece of Saran wrap is not the time to contemplate installing a new air-conditioning system.

The rest of the AIM Marine Group team know about this rule all too well, which is why during our refit of Arawak, a 1996 Grand Banks 42, one of our first calls was to the experts at Technicold, a marine air-conditioning manufacturer and subsidiary of Northern Lights. With ambitions to cruise the Caribbean, and South Florida, our request was simple: help us find a robust air-conditioning system that will perform well both in the tropics and in New England.

Fresh air can't be beat. But you may want to consider replacing your air conditioner before heading south.

Fresh air can't be beat. But you may want to consider replacing your air conditioner before heading south.

But let’s back up; as with any refit project, choosing the right manufacturer is the first and sometimes most important decision a boater needs to make. When researching providers, two things directed us towards Technicold; first was a wealth of service centers up and down the East Coast, where we’ll be doing most of our cruising. With 13 dealers in Florida alone, assistance and/or spare parts from Technicold are never too far away.

Secondly, we were impressed by the robust construction. Where some companies use components from molded plastic, Technicold employs 3/16-inch stainless steel, and not just for their condensers but also for ancillary components such as fasteners, shrouds, and the drain pan. This should help the system withstand the hot and humid engine-room environment well. Custom two-part enamel paint on the system provides yet another layer of protection from the harsh environment. A standard one-year warranty on parts and labor and a two-year warranty on all parts inspired confidence in our new split DX system.

Why was this type of system chosen for the Grand Banks 42? When diagnosing the cooling needs ofArawak, Technicold technicians ran a complete heat-load analysis—which they do for every customer—that calculates the size of the living areas and factors in the cruising climate that the owner plans to frequent. (Boaters who cruise the Caribbean will obviously have higher power demands than those who cruise the Great Lakes.) This information allows them to determine the most efficient system for your vessel.

It was determined that with three staterooms and two heads, our Virgin Islands-based vessel would benefit nicely from a split, Direct Expansion (DX) system. And, of course, installing this would require replacing the old, self-contained units we already had onboard. This split DX unit would operate quite differently from our old self-contained system, which pumped seawater throughout the boat to individual air-conditioning condensers and fans that inhabited each living space. In a split DX unit, seawater is pumped just a few feet to a single (larger) system which sends cooled refrigerant throughout a vessel, like blood to your fingertips.

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“When converting a boat with self-contained units to a split DX system, you’re moving the condensers to the engine room, which gives you quieter operation versus a self-contained unit where all the condensers and compressors are located in each living space,” explains Shaun Hall, global sales director for Technicold Marine Systems. “With the new system you’ll no longer have to hear them clicking on and shutting off. And you eliminate a lot of added vibration throughout the boat.”

This is a nice feature, especially for those who like to enjoy quiet nights at the marina or out on the hook; but Hall explains that there are going to be several other upsides to our new system.

“Instead of running seawater throughout your vessel [as in a self-contained unit] for cooling, in a split DX system you’re running refrigerant lines. So you’re still running fluid throughout your vessel but running refrigerant can be easier,” says Hall. “There’s less required maintenance compared to seawater lines that constantly need to be descaled.”

Running new copper refrigeration piping throughout Arawak sounds like a daunting task (and depending on available access, it may be) but we’re not reinventing the wheel; we’re hoping Technicold’s technicians will be able to run her new (Armacell-insulated) copper where her old seawater pipes were, or at least come close. Note: Federal regulations require a liscensed technician to purchase and handle the refrigerant so we recommend leaving this job to the professionals.

Hall predicts that complete installation of the new system will take five business days with two technicians working on it. But he warns: “When dealing with boats, things are subject to change.”

The model we’re installing is what’s known as a “straight cooling system,” which as opposed to a reverse-cycle system, only provides cooling, not heat. Should Arawak venture into the colder climes of Nova Scotia, Hall says adding heat to the system is an easy fix. “The Technicold units have a built in access port where you can insert an electric heat strip. Just wire it to the control board and you’re all set,” says Hall. “It’s a permanent heating device that can stay in there year round and it only takes a couple hours to install.” That time estimation, as always, is dependent on onboard access and the number of condensers that must be dealt with.

The research stage of our marine air conditioning journey is now in our wake. Now, together with our partners at Technicold, we’re looking forward to the exciting part: Installing the unit and then putting it to the test. Follow our journey to breathe new life (and colder air) into Arawak at

A Cool Touch

One display = 19 control zones.

One display = 19 control zones.

Luckily for us the timing of our refit coincides with the launch of Technicold’s new color touchscreen interface that the company says will make the user experience easier than ever. It will allow us to quickly set a desired temperature and fan speed for up to 19 zones, as well as let us control the relative humidity throughout our vessel.

Technicold, 800-843-6140;

This article originally appeared in our affiliate, Power & Motoryacht, and can be seen here.