Check circulation pump... What needs to be shut off?

Hello everyone,

apparently the circulation pump in our house is no longer working. It stood still for a long time, and I read that these things tend to seize up and can be made operable again after disassembly.

So far, so good. But now I don’t know what I have to shut off before I remove the pump. Basically, apart from the main shut-off lever, I only have two shut-offs in the entire system. One from the cold water to the tank and one from the tank towards the hot water. All other pipes have no way to be shut off.
Now the question is how I can "dry out" the pump. There is also actually a small brass screw right above the pump with which you can shut off that side. In my case, however, the screw is hollow and it looks as if it has an internal thread. In any case, I cannot turn it with a screwdriver.
And if I simply close the two valves I still have, the entire water from the circulation circuit will still drain out as soon as I remove the pump, right?

I am a bit puzzled here. Does anyone have an idea?

Thank you very much and best regards
Garmir

So, I don't know what kind of circulation pump you have installed. But usually, there is a screw in the pump that you can unscrew and then use a screwdriver to push the pump wheel or check if the pump wheel is turning or if there is a mechanical fault. It is sufficient if the pump is switched off for this.

The pump does not need to be removed for this. And because this happens quite often, it is actually designed that way by the pump manufacturers.

It is a "Star-Z NOVA (DE)" from Wilo. Unfortunately, this is the version without a shut-off and non-return valve. If I unscrew the motor head here, the pipe is open. Therefore, my question is how I can prevent all the water from running out of the circuit when I dismantle it. I'm not concerned with removing the entire pump, but with dismantling the motor head so that I can make the rotor movable again.