When do plate humidifiers operate?

Plate humidifiers are designed to operate whenever the fan is running. This is because the fan must distribute the moisture generated by the humidifier throughout the space effectively. When the fan operates, it creates airflow that allows the moisture to be delivered into the air, increasing humidity levels throughout the environment. If the humidifier were to operate independently of the fan, the moisture may not disperse properly, which could lead to localized humidity levels or potential issues like condensation. Therefore, it is essential for plate humidifiers to work in conjunction with the fan to maintain optimal humidity control and comfort.

In this context, the other options do not accurately describe the operation of plate humidifiers. They either limit the operation to specific fan speeds or suggest conditions that could hinder effective humidification.