YOU CAN BUY ALL THESE PARTS FROM PLUMB CENTRE THEY WILL ORDER THEM. THEY SHOULD OF FITTED A INLINE MAINS WATER FILTER BEFORE THE BOILER. OR NEVER POWER FLUSHED THE SYSTEM BEFORE INSTALLATION WHICH IS PART OF THE REGS NOW. THIS WILL HAPPEN ON ANY BOILER IF NOT LOOKED AFTER .
HI-SPEC PLUMBING, October 2006