Humidistat on Power Attic Ventilator

The manual for a Certainteed All Season ASR-HP Roof Mounted Power Attic Ventilator states, under the "Humidistat" section, to "ground to screw on box". Does this mean that when you ground the scew on the box, it becomes humidity driven and not temperature driven? So every summer you disconect for temperature and reconnect it in the winter for moisture? Website provided no help.
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