A filling unit with a pump is a system of a thermostatic valve, a pump and thermometers. It is used to ensure and maintain a high temperature of the return water to the boiler. This parameter contributes to protection against low-temperature corrosion.
The advantage of load units over thermostatic valves itself is that you get an overview of the temperatures on the individual branches. As the circulation pump is included, it is not necessary to buy another pump separately. It is therefore a cost-efficient price package.