C220 cdi w204 cooling pump issue

[Festamb1]

Hi help needed please
I have a 10 plate c220 cdi that has had a new water pump fitted 6 months ago and I have an issue under the bonnet where the engine seems to be getting very hot but not overheating I have had some perished vacuum hoses changed on the switch over valve above the pump also but it seems to me that the water is not circulating correctly can somebody explain what the vacuum pipe that goes to the water pump is for please.
Many thanks

 

[pcthrillrider]

well the pump can be shut off electrically is the connector reconnected? could be a faulty thermostat stuck shut also electric

 

[Festamb1]

Hi I can’t see a electrical connector on my pump the only thing I can see is a vacuum pipe on the top of it and above that is the switch over valve which I don’t know what’s this does.
I had a thermostat fitted a couple of weeks ago this was a main dealer part so this should be ok