Troubleshooting Boat Fridge Issues When Docked: Power Conundrum

A boat's refrigerator is usually the biggest drain on its power supply. Problems with boat fridges are almost always caused by a lack of decent insulation. Refrigeration systems on boats are incredibly efficient, and if they are pulling too many amp hours, insulation is the most likely cause. The type of foam used for insulation is also very important. It needs to be high-density, polyisocyanurate closed-cell foam, which is highly energy efficient and waterproof. The condition and design of all door seals are critical for the performance of all types of boat fridges.

Poor insulation

When insulating a boat, it's crucial to seal all edges and gaps to prevent moisture from getting behind the insulation, which can lead to condensation and mildew growth. This can be done by bonding the insulation tightly to the surface using contact cement or self-adhesive. For hard-to-reach areas, a combination of self-adhesive and contact cement can be used. It's also important to fill all seams with caulk to prevent thermal bridges and condensation.

In addition to the methods above, there are other ways to improve the insulation of your boat. For windows, bubble wrap can be an effective and inexpensive solution. Simply cut the bubble wrap to size, mist the window with water, and press the wrap in place. This will help insulate single-glazed windows and reduce heat loss.

Furthermore, adding an extra layer of insulation, such as silver reflective material, can significantly improve the insulation of your boat refrigerator. This can be done by lining the inside of the refrigerator with Reflectix or a similar product.

By following these steps and choosing the right materials, you can effectively address poor insulation issues on your boat and create a more comfortable and energy-efficient space.

Bad door gaskets or seals

A common issue with boat fridges is a lack of decent insulation. Older models, in particular, may have thin layers of cheap, low-density porous foam, which can cause the cold air to leak out through the seams.

To test the seals on the whole perimeter of the door, repeat this process at various points around the door. If the bill can be pulled out without resistance, then the gasket may need to be adjusted or replaced. If you can see any gaps or holes in the gasket, then it definitely needs to be replaced. A gap of 1/8" by 8" is equal to a one square inch hole in your fridge.

If your boat fridge is top-loading, the lid may be held in place only by gravity. In this case, you can fashion latches to hold the lid down more tightly and securely.

High ambient temperatures

The condenser coils, which expel heat from the refrigerator, work harder and become less efficient as external temperatures rise, leading to higher energy consumption and potential wear and tear over time. The compressor, which circulates refrigerant and maintains internal cooling, also operates more frequently in hot conditions, reducing its lifespan and increasing energy usage.

Additionally, the evaporator fan, which facilitates airflow throughout the unit, becomes more crucial in high temperatures. It must work harder to evenly distribute cold air and disperse heat to counter the hot air entering the fridge.

To mitigate the impact of high ambient temperatures on your boat fridge, consider the following:

• Positioning: Place the fridge away from direct sunlight and heat sources to maintain cooler ambient temperatures and reduce the workload on the refrigeration system.
• Maintenance: Regularly clean the condenser coils to ensure efficient heat expulsion and optimal performance.
• Internal organisation: Optimise the internal arrangement of the fridge by storing items in a way that allows for unrestricted airflow. This ensures even cooling and prolongs the lifespan of perishable items.
• Insulation: Upgrade to high-quality insulation to reduce energy consumption and improve performance in high-temperature conditions.
• Smart thermostats: Invest in smart thermostats that can automatically adjust to changing temperatures, helping to maintain optimal cooling and energy efficiency.

Restricted airflow at the condenser

To prevent restricted airflow, it is important to regularly inspect and clear the vents in both the refrigerator and freezer compartments. It is also crucial to avoid overloading the refrigerator and to ensure proper airflow by creating space between items. Additionally, the fan and coils should be regularly inspected and cleaned to ensure optimal performance.

The consequences of impeded airflow can include uneven cooling, with some areas becoming too cold and others too warm, leading to food spoilage. It can also result in increased energy consumption as the refrigerator has to work harder to maintain the desired temperature, which can lead to higher utility costs and a shortened appliance lifespan.

To restore proper airflow, it is recommended to check and clear vents, avoid overloading the refrigerator, inspect and clean the fan, clean the coils, and defrost the freezer if ice has accumulated around the vents.

By understanding the causes and addressing airflow issues, boat owners can ensure their refrigerator operates efficiently and effectively, maintaining food freshness and safety while minimising power consumption.

Evaporator covered in a thick layer of ice

If your boat fridge's evaporator is covered in a thick layer of ice, it's time to defrost! While a thin layer of frost is normal, a thick layer of ice will act as an insulator, making it harder for the fridge to cool. This is because ice is a great insulator, so when there is a thick buildup of ice on your evaporator, the heat from your fridge can't be removed quickly. This means that the heat from the ambient environment around the box is able to heat the box faster than the ice-covered evaporator can remove it, causing your fridge to run constantly as your box temperature slowly rises.

The ice is likely to be the result of moisture in the ambient air that enters the fridge every time you open the door, from uncovered food items, and from air infiltration through gaps in the gaskets and door seals. The air pressure in a 35-degree box is lower than the air pressure in a 70-degree galley, so that warm moist air is actually pushing itself into your fridge. If you have a front-loading fridge, every time you open the door, all the cold air falls out at your feet, and the warm moist air is sucked into the top of the opening. Top-loading freezers and fridges don't have this problem.

If you find yourself defrosting more often than every few weeks, check your door gaskets. You can do this by using the dollar bill method: close your fridge door on a dollar bill. You should not be able to easily pull the dollar out. Try this all around the perimeter of the door. If it slides up and down the gasket easily and can be pulled out without the gasket grabbing it, then you may need to adjust your door catch or the door hinges. Otherwise, you may need to replace the gaskets, especially if you can see any gaps or holes in the gasket. A 1/8" gap that is 8" long is equal to a one square inch hole in your fridge.

Remember, never use metal scrapers or tools to remove ice, as you could seriously damage your evaporator.

Frequently asked questions