DIY Doctor UK DIY Forums

hi all.
i have been having problems with my boiler making a noise and the overflow pipe pouring out hot water from tank in loft..a heating engineer came out and said i have a section off blocked pipe. he thinks its lime scale and sludge..will a product like fernox flush out the blockage or will i need a plumber to replace part of my pipes any advice will be appreciated..
Many Thanks
Colin

are you getting heating and hot water ? if so probably faulty boiler thermostat, the tank will bve boiling over and the water will be discharged down the overflow pipe, cant see any pipes being blocked if heating and water are working.