Multibona- Little water

Hello dear community
,I have a problem with
a Multibona from Kaffeepartner.
I bought one used and repaired it and it works perfectly.
But
recently it has been causing
problems.

When the machine has not been used for a while (about 15 minutes) it only gives off very little hot water. Or just drinks that are prepared with milk powder. It then releases water for about 2-3 seconds. This is why the mixer is always clogged because there is not enough water to make/rinse. Coffee dispensing

is normal.

Now the clou, if I press the hot water button once after a longer period of time, only a little comes out, if I press it again, exactly the amount I want comes out and also the milk drinks are all

tip top.

Can anyone help me or tell me what this could be? What kind of defect could it be or does it have something to do with programming

?

Greetings Markus