how can i fix my worcester 350 combi boiler?

if boiler works ok and system presure is ok at 1.5 bar when cold then warning water presure sensor is bloked up propably when you moved boiler the small opening to sensor was full of sludge and has dryrd out when no water in unit drain boiler remove sensor and clean out inside opening with very say ,small allen key ect

tony.tsp heating
July 2007