What is a common reason for a refrigeration system to fail to activate cooling?

A common reason for a refrigeration system to fail to activate cooling is a faulty thermostat. The thermostat serves as the control center for the refrigeration system; it monitors the temperature and signals the compressor to turn on or off. If the thermostat is malfunctioning, it may fail to properly detect temperature changes, leading to the compressor not activating when it should. This can result in the refrigeration system being unable to maintain the desired cool temperature, thus failing to cool effectively.

In contrast, low ambient temperature can cause a refrigeration system to operate less efficiently, especially in specific designs that are not suitable for very low temperatures. Excessive refrigerant can lead to issues like flooding or compressor damage, but it generally wouldn't prevent the system from attempting to cool. Poor insulation can result in heat gain or loss but does not directly affect the activation of the cooling cycle itself. Therefore, the faulty thermostat is the most likely culprit for the failure to activate cooling in a refrigeration system.