GAS EC5 Fan Controller & Balancer The GAS EC5 Fan Controller & Balancer Revolution is built to control Systemair EC fans. The unit comprises an RTT (Reactive Temperature Technology) system, which helps it react to environmental changes. Temperature changes allow the controller fans to react and maintain the target temperature. A consistent temperature in the grow room will allow you to achieve high harvest yields and top-quality crops. The fan controller is made for use with SystemAir's Revolution EC Fan.