What condition can terminate a defrost cycle?

The condition that can terminate a defrost cycle is related to the suction pressure within the refrigeration system. During a defrost cycle, the evaporator coils are heated to remove frost or ice build-up. This process is crucial for maintaining efficient operation and ensuring that the refrigerant can effectively absorb heat.

When the suction pressure drops below a certain threshold, it often indicates that there's insufficient refrigerant flow or that there may be a cooling issue, and continuing the defrost cycle may not be beneficial. This drop in pressure can signal the system to terminate the defrost cycle to protect the compressor and the overall integrity of the refrigeration system.

In contrast, conditions like low ambient control, condensing temperature, and head pressure play important roles in the refrigeration cycle but do not directly dictate the termination of the defrost cycle in the way that suction pressure does, which provides immediate function-related feedback about the unit's operational state during defrosting.