Intervent BVF100H Axial Extractor Fan 100mm / 4 Inch (Humidistat/Timer Model)

Normally used in bathroom or toilet locations.This model has a built in humidity sensor which automatically activates the fan when condensation is detected. It will then continue to run until the condensation is cleared, and the run on time has elapsed. It can also be operated in conjunction with the room light switch. When the light is switched on the fan will run on and continue to run on for a pre-set time after the light is switched off. The fan should be left switched on with a constant power supply connected at all times. Additionally it requires permanent live, switched live and neutral (3 wires excluding earth) connected if the timer via light switch functionality is required.