Worcester Bosch Thermotechnik 280 RSF - The heating system pressure gauge?

Lowering the pressure - heating system pressure gauge.?
I have this boiler and i cant seam to get the pressure to go down to the correct position. How can i do this? I have looked on the internet all evening for a fix and I cant seam to find the answer i want. Does anyone know how I can do this? (PS: it is getting very cold in the house :( and no hot water!)

It keeps raising to the max and cutting out,,,

Please help!!!! - Thanks everyone!!!!