What do hunting and surging in a DX system indicate?

In a DX (Direct Expansion) system, hunting and surging are indicative of over-adjusted or too much sub-cooling. When the temperature and pressure controls are overly sensitive or set incorrectly, it causes the system to frequently turn on and off as it attempts to maintain the desired temperature. This creates fluctuations in the cooling output, often resulting in the compressor cycling more than necessary, which can lead to a hunting behavior.

Surging, on the other hand, describes the phenomenon where the refrigerating effect falls below the evaporating conditions. This situation can arise if there's excess refrigerant or sub-cooling, pushing the system into a cycle of instability. If the system is assessing demand inaccurately due to these adjustments, it leads to erratic running behavior, which corresponds directly to the symptoms associated with excessive sub-cooling.

Thus, recognizing hunting and surging as signs of an imbalance, particularly from too much sub-cooling, helps operators identify and correct these issues, ensuring the system runs efficiently and performs as intended.