The thermowells of the DualSun 200-300 2E water heater have a diameter of 12 mm, the bottom tank probe supplied in the DualSun essential kit is a PT1000 6 mm probe.
It is not necessary to adjust the probe into the thermowell.
To ensure proper heat transfer between the thermowell and the probe, thermal paste can be placed around the probe before inserting it into the thermowell.
In addition, the thermowell is insulated from the outside by a gasket. To make sure that the probe is completely isolated from the outside air, it is possible to place an insulating adhesive over the entrance of the thermowell.