SIR 321 is a Z-Wave Plus countdown timer with one relay and support of duration base schedule that can be used to control any electrical appliances rated up to 3 kW.

With an external temperature sensor, SIR 321 can measure room temperature and send temperature report on regular interval or delta temperature change as per configuration.

It forms part of central heating control system, it can be operated by any third party controllers using ‘Binary Switch command class’ commands.

SIR 321 will act as a repeater once added into the Z- Wave network, providing an alternative communication route for units which otherwise would not be within communication distance of each other.

SIR 321 has a fail-safe mode where by the relay is turned OFF if another 'Binary switch SET' or 'Basic SET' command has not been received within 60 minutes.