The button on the mash tun stays lit when the control box heating socket is providing the mash tun with full power. In this case, the heating status bar on the control box screen will show 100%.
When the temperature being measured approaches the desired target temperature—specifically, when it is within a margin of less than 2 degrees—the control box adjusts the power supplied to the mash tun to prevent overheating or overshooting the set point. Instead of delivering a continuous, full power output, the control box reduces the energy supplied by pulsing the output voltage. This pulsing is achieved through the use of advanced power electronic devices that modulate the voltage in a controlled manner. As a result, the mash tun receives an intermittent sinusoidal voltage rather than a constant one. This means that the power delivered is not steady but is switched on and off rapidly in pulses, allowing for finer control of the temperature. This pulsed delivery of power is responsible for the blinking behaviour of the switch, as it visually indicates the intermittent nature of the voltage being sent to the mash tun. This method helps maintain the temperature within the desired range more accurately and efficiently.