... and so on. digital thermostat:Model 509 Programmable Heating Thermostat509 series, large LCD digital thermostat, 110/220VAC±10%,16A thermostat for hot water radiant ... : The temperature of every corner is different by convection. The thermostat can be adjusted the valve range from -8°C to ... ” button and hold it for more than 6 seconds, the thermostat will enter setting mode, and press up or down button ...