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Central Heating

Plastic piping and radiator 'sludge'

I had my cental heating system powerflushed 5 years ago( 7 years after moving in to the house). The system had been installed about a year before I bought the house so I've no idea if it was flushed on instillation. The 'black sludge' is back. In the last 20 months I have had to replace 4 radiators which have corroded and leaked - the last 2 happened when they were put back after being removed to allow for decorating. I've now discovered the pipes are plastic not copper and because of this the powerflush was only guaranteed for 1 year. I've been told that the plastic piping lets air/oxygen into the system (?) and that the problem will just keep coming back unless this is replaced with copper pipe. I've been told I'd be wasting my money having the system flushed again while I still have the plastic pipes. Is this true? Surely plastic piping wouldn't be used if this was the case. I don't want to needlessley replace the piping but also can't keep relacing radiators.

3 Answers from MyBuilder Heating Engineers

hi , if you change your pipes to copper they will still need to be power flushed after to remove any flux or bits of copper in the pipe work.


Answered 10th Nov 2012

If the plastic is not labeled as barrier pipe then yes it can let oxygen in on a molecular level as plastic is a polymer. This means that its structure is made up in a jail cell like way that will allow molecules to pass through into the water. This can and does wreck the system.
But other problems can also allow oxygenation of the water. Pump over is a classic cause , thus constantly introducing air into the water.


Answered 12th Nov 2012

I can't see the pipework inducing the amount of air you mention, sounds like the system is pumping over, is it fed through a expansion tank, get a proper plumber out and not somebody that wants to sell you something.


Answered 12th Nov 2012

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