How can i adjust the water pressure on my Servis M6666 washing machine?

How can i adjust the water pressure on my Servis M6666 washing machine? An engineer came and replaced a leaking fill draw and turned the pressure in the machine down as he said it was too high now i think the pressure is too low as my pipes and bolier clunk, shake etc whilst it fills unless i release sone pressure by turning a tap on from the pipe that supplys it, so i would like to know how to adjust the pressure up