Why you may hear the chiller fan cycling more frequently as temperatures get closer
When the outdoor (ambient) temperature gets closer to your set water temperature, especially in cooler weather, it’s completely normal for the chiller to sound like it’s turning on and off more often.
What most people are actually hearing in these situations is the cooling fan, not the compressor.
Here’s why this happens:
At cooler ambient temperatures, the chiller releases heat more efficiently. Because it cools itself down quickly, the fan doesn’t need to run for long periods.
Instead of running continuously, the fan will turn on briefly to cool the internal components, then shut off, repeating the cycle as needed. This can make it sound like the unit is cycling frequently, even though it’s operating normally.
As the water temperature approaches your set point, the system makes only very small adjustments to maintain it. That fine-tuning naturally results in shorter, more frequent fan cycles.
In warmer weather, the opposite happens:
The chiller has to work harder to shed heat, so the fan runs longer and more steadily.
Because the fan doesn’t stop and start as often, customers tend to notice it less, even though the unit is actually working harder.
The key takeaway:
Frequent fan cycling in cooler conditions, especially when the water temperature is near your setpoint, indicates the chiller is operating efficiently and performing as designed.