Hi Sinex666,
If all the radiators equipped with Tado smart radiator valves (TRVs) were set to 18 degrees Celsius, while the Nest thermostat was set to 20 degrees Celsius, the Nest Thermostat would continue to operate based on the setpoint of 20 degrees Celsius. It would measure the temperature in its immediate vicinity and activate the heating system (e.g., boiler) to maintain the desired temperature. The Tado TRVs on each radiator would individually regulate the flow of hot water into the radiators based on their setpoints of 18 degrees Celsius. Since the setpoint on the TRVs is lower than the Nest Thermostat's setpoint, the TRVs would restrict the hot water flow to the radiators to maintain the lower temperature.
As a result, the radiators with Tado TRVs would limit the heating output, and the temperature in those rooms might not reach the desired 20 degrees Celsius set on the Nest Thermostat. The Tado TRVs would act as local temperature controllers, independently regulating the heat output in each room based on their individual setpoints. It's worth noting that the actual temperature achieved in each room would depend on various factors, such as the insulation, heating capacity, and heat loss of the room. Additionally, the precise behavior of Tado TRVs can vary based on the specific settings and configuration.
If you have a multi-zone heating setup with Tado TRVs and a Nest Thermostat, it's generally recommended to ensure that the setpoints on the TRVs and the thermostat are coordinated to achieve the desired temperature balance across different rooms or zones.
Let us know if that helps.
Best,
Zoe
