Pressure is high on boiler

[Nordiclaura]

Recently had a boiler service and prior to it been done the pressure was in the sweet zone green 1. Now the service has been done its up in the red, obvs more water was put in, fir what reason I have no idea. How can I get it back down and in the green??

 

[Geofd]

Drain a little water from the boiler what's the #on the pressure gauge normally at , note what it is when the boiler is not running,and cooled down and also what it is when it's running, add water slowly, if you add while it's hot you could crack the boiler let it cool down