seems to look like asolid work. not yet tested. delivery time was too long :-(
The "Nominal pressure: 0MPa" is wrong, the device actually needs some pressure and it's more than a drain pump can provide. However, the network water pressure is enough and being connected to the regular water supply it works as described. So I was fooled with "Nominal pressure: 0MPa" and cannot use the heater in my project.