Technical Bulletin: Refrigerator Performance During Cold Weather

As we move into the colder months, many boat owners begin to notice changes in how their onboard refrigerators behave. These issues arise year after year and are usually linked to low ambient temperatures rather than a fault with the appliance. This bulletin explains why it happens and what you can do to reduce the impact.

Why Low Ambient Temperatures Cause Problems

Most refrigeration appliances supplied in the UK, including those fitted on boats, are Climate Class N (Normal). They are designed to work correctly in ambient temperatures between +16°C and +32°C.

Inside the fridge, the normal operating temperature is between 0°C and +10°C. When the ambient temperature around the appliance drops into this same range, particularly in unheated cabins or when the boat is left unattended, cold air can work its way into the cabinet.

The internal thermostat then detects that the fridge already appears to be at its target temperature. As a result, the compressor does not run. Over time, the freezer or ice-box may slowly defrost even though the appliance is still switched on. This is one of the most common winter enquiries we receive, and it is almost always caused by the surrounding temperature rather than any mechanical fault.

Ways to Reduce Cold-Weather Operating Issues

• Add a small amount of background warmth.
  Raising the ambient temperature slightly helps the thermostat read the internal temperature correctly so the compressor can operate as intended.
• Empty the freezer or ice-box if the boat will not be used.
  If the surrounding temperature drops into the fridge’s operating range, an empty freezer section helps prevent slow, unintended thawing.
• Adjust the thermostat temporarily.
  Turning the thermostat down encourages the fridge to continue cooling despite the cold conditions. This may lead to longer running times, but it helps maintain frozen goods. When temperatures improve, always return the thermostat to its normal setting to avoid over-cooling.

Summary

If your fridge seems inactive, the compressor doesn’t run, or the ice-box begins to thaw during cold periods, it is usually due to low ambient temperatures rather than a fault. Understanding how cold weather affects climate-classed refrigeration, and taking a few simple steps, can help maintain more reliable performance throughout winter.

If you need more specific advice for your setup, you are welcome to contact us.