Thank you very much for your reply!
I'm guess my problem is the motor too, because I've replaced the valve fully, however not sure about it. Now it's not clear for me what helped for you, have you changed the valve or the motor on it (maybe bad wording only)?
hi benedekl
The fault with mine was the motor on the diverter valve. The motor wasnt working correctly. Apparently if you listen carefully, you can hear a click as the motor kicks in to divert the water from heating to hot water. There was no click so i changed the valve, cost me about £20, and its worked fine ever since.
I'm guess my problem is the motor too, because I've replaced the valve fully, however not sure about it. Now it's not clear for me what helped for you, have you changed the valve or the motor on it (maybe bad wording only)?