Call a QUALIFIED GAS SAFE PLUMBER- DONT MESS ABOUT WITH WHAT YOU DONT KNOW ABOUT!! iT CAN BE SERIOUSLY DANGEROUS AND AN OFFENCE UNDER THE GAS SAFETY AND INSTALLATION ACT 1984 TO PERFORM ACTS ON A BOILER FOR WHICH YOUR NOT QUALIFIED
GEEEZ, AND THEY CALL SOME OF US COWBOYS!!
GAS SAFE PLUMBER, January 2010