How to Choose a Fan Controller

Technology Considerations

Below are the main technology considerations when deciding how to choose a fan controller, along with wether you need EC technology or AC technology.

Thermostatic Controllers

Simply set a temperature and your fan speed will increase or decrease to maintain the set temperature.

Bandwidth

The difference in temperature between the minimum and maximum fan speed. If bandwidth is set at 2°C and temperature is set at 24°C, your fans increase from a minimum speed at 24°C and run to a maximum speed at 26°C.

Fan Balancing

When using an intake/outtake fan, negative pressure is required (more air out than in). Fan balancers achieve fine control to create negative pressure.

Humidity Settings

Select a maximum humidity set point and the fan will ramp up as the humidity increases. Be careful with this setting as it will override your set temperature if the intake air is humid it will run your fans at maximum speed.

AC Controllers

AC fans have to be controlled by changing the mains 230V power supply. This can be done by either:

1. Using a triac controller, which cuts the mains signal very quickly, stopping and starting the power to reduce the speed of the fan. This can cause the fan to buzz at low speeds.
2. Using a 5 step hybrid transformer controller, which changes the voltage of the mains power from 230 volts to different steps; 190V, 170V, 140V, 90V etc. Step controllers are efficient and allow the fan to run at low speeds without buzzing, prolonging the life of the fan motor.

EC Controllers

EC fans have built-in electronics within the motor, they are controlled by providing a 0 -10 volt signal. An EC controller will regulate fans between 1% and 100% power with no buzzing or humming. They use less than half the power at half speed than an AC fan.