Dear all, we had the Vitocal 222-S E.06 2C heat pump installed a few weeks ago and after the heating season started we found out that one of the wall radiators at our home is not heating properly. It is the one that is the most far away from the heat pump on the second floor. All the other radiators on the same floor are working fine as well as the floor heating (downstairs).
The radiator valve on this problematic radiator is always fully open, the heat pipe going in is warm, some parts (around half) of the radiator is also warm but the return pipe from the radiator is always cold. We also made sure that there is no air in the radiator that could cause similar problems. It is completely new and it is this particular type with pipes connection in the middle: https://www.korado.com/radik-line-vkm8
Our heating system is rather small (floor heating downstairs), 4 wall radiators upstairs. Total water volume is 120 litres. The distance from the heat pump to that problematic radiator is around 15-17 meters (incl. one floor around 3m in hight)
One of the possibility that I would like to eliminate is that it is caused by the insufficient flow of warm water of one of the two Grundfos circulation pumps. Since their speed can be set by the PWM signal, I would like to increase it but I do not know how. Please can anyone help? Also I would like to know what is the default setting for the pump speed it is currently set on.
Thank you,
Pavel
