Taking care of your marine refrigeration systems

Of all the essential products we rely on – and take for granted – in our day-to-day lives, the humble refrigerator ranks particularly highly. It goes about its job quietly and efficiently, without any supervision. It’s the perfect appliance.

Then disaster strikes. Your fridge breaks down and suddenly you no longer have the luxury of reaching for any chilled foods or drinks. It’s a nightmare.

You begin to regret not paying your refrigerator more care and attention when it was fully operational. It scares you enough to vow never to take it for granted again.

Taking care of your refrigerator at home is important, but it doesn’t come remotely close to the importance of looking after a marine refrigerator aboard a superyacht. Not only is it much more complex and specialised, but a failing marine refrigerator can prove genuinely catastrophic if the yacht is positioned hundreds of miles away from land.

With this in mind, Yachting Pages enlisted the advice of HVAC & Refrigeration (HVACR) experts MTSea, Technicold by Northern Lights and Heinen & Hopman Engineering B.V. to highlight the key things superyacht crew need to remember to preserve the on-board refrigerator – and optimise its performance.

The most common superyacht refrigeration problems

There are a number of reasons why a fridge or freezer could fail or under perform. Improper maintenance and age are two of the most common, while an unrealistic user expectation of an appliance’s cooling capabilities is also a surprisingly prevalent issue.

Mark Critchley, of MTSea, surmised, “Often, it is just high expectations of what a unit on a yacht is actually capable of. A freezer that is only capable of getting down to -15 degrees is never going to reach -22 degrees. Likewise filling a 200l freezer with 100kg of fresh meat and expecting it to cool to -20 degrees overnight is just never going to happen.”

Let’s tackle this somewhat surprising issue straight away: As soon as you become responsible for a marine refrigerator, talk to the engineer and discuss the appliance’s capabilities. This will prevent any shocks further down the line.

Discussing the most common issues our experts face when called upon by clients, they noted low or poor cooling, no cooling at all, icing up of evaporators and high-pressure issues with condensing units.

What causes these issues? More often than not, poor maintenance and monitoring.

“The most common problem we see is improper or untimely maintenance,” Kevin Wiebusch, of Technicold by Northern Lights, explained.

“This results in sea water components fouling with grass, barnacles and debris, leading to accelerated wear on components and reduced life of the system. This ultimately leads to damage to condensing coils and, if not properly monitored, can lead to catastrophic failure of the entire system.”

Crew advice: How to maintain a superyacht HVACR system

Ensure regular maintenance of the on-board refrigerator

HVACR systems historically clock up higher running hours than any other system on board, and thus a proper maintenance schedule needs to be formulated to ensure the refrigerator is operating correctly.

“All manufacturers supply a basic service and maintenance schedule in system manuals,” Kevin Wiebusch noted. “However, depending on the vessel’s location, conditions may require a more frequent inspection and cleaning regiment for the condensing coils. Some warm nutrient-rich waters will foster accelerated marine growth and quickly require attention.”

Wiebusch added, “Also be aware that the raw water circuit is not limited to only the condensing coils but includes the entire run of plumbing from the thru-hull, strainer, pipes and hoses to the HVAC unit as well the discharge side of the pipe run. Any restriction will affect water flow and performance of the equipment.”

Always keep your marine refrigerator clean

Cleaning a refrigeration system, inside and out, is also highly important in preserving its optimum level of performance. It helps to prevent pests, bacterial contamination and the growth of mould.

HVACR expert Eric van Dijk, of Heinen & Hopman, said, “Preventing mould growth is achieved by controlling condensation, moisture and removing materials contributing to mould growth. Regular cleaning schedules for cold rooms prevent mould or contamination issues. Good housekeeping should help to discourage pest and vermin, but routine inspections should be carried out.”

Five expert refrigeration tips

With the help of our experts we have compiled a pocket-sized list of five tips that all crew should consider if they are responsible for maintaining the on-board refrigeration system:

• Keep sea water and air filters clean
• Look after door seals and replace when they start to fail
• Acid flushing and an annual health check of the system for a single-season boat and bi-annually for a double-season yacht
• Use a reputable refrigeration company to maintain equipment
• If you have not been trained in the use of refrigerants, do not add refrigerant to a system that you think is low on gas – the gas will be low for a reason and this needs to be remedied

How often should a marine refrigerator be serviced?

As previously mentioned, all manufacturers publish a recommended service and maintenance schedule, but it’s the responsibility of the operator, crew or engineer to undertake frequent inspections when there are any signs of performance issues.

Crews should plan to have a licensed marine HVACR professional perform a service on all refrigeration units during the yacht’s seasonal maintenance, or in the event of any equipment failure.

How often should refrigeration systems last before needing to be replaced?

There is no ‘one size fits all’ answer to this question. It can vary depending on a host of factors, including how the system is maintained, who manufactured it, where it’s located on board and whether it’s seawater-cooled or air-cooled.

Kevin Wiebusch commented, “The life of any HVACR system is directly related to proper maintenance and cleaning. Remember these systems are pumping raw water sometimes 24 hours a day for months on end. There is no other piece of equipment on board that is subject to more destructive wear and tear from seawater than an HVACR system.

“A properly maintained system, however, should offer many years of reliable service.”

Interestingly, Mark Critchley cited that the health of major components is something to keep an eye on.

“We [MTSea] expect to see major components on systems start to need changing at around the 10-year stage, however if one component is failing due to use and age it is probable that other components are also nearing the end of their life. It makes practical and financial sense to consider replacing the whole unit and avoid years of regularly taking the system apart to address different issues.

“Saying that we do see well maintained systems still happily working at 25 years – each system needs to be individually assessed.”

Discover how to stay cool with superyacht climate control.