What can initiate a defrost cycle?

A defrost cycle in refrigeration systems is primarily initiated by a timer, which is designed to periodically trigger the defrost process based on a predetermined schedule. This is crucial for maintaining the efficiency and effectiveness of the refrigeration system by preventing excessive frost buildup on evaporator coils.

Timers are set to activate the defrost heater at specified intervals, allowing for a systematic approach to maintaining optimal performance. While other components like the defrost thermostat can also play a role during defrost operations—by serving as a safety mechanism to terminate defrost if temperatures exceed a certain threshold—it's the timer that initiates the cycle based on set time intervals, ensuring that frost is controlled without requiring constant monitoring.

Hence, understanding the role of timers in managing defrost cycles is essential for effective refrigeration system maintenance.