HCL to clear blockages central heating

31 May 2007
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United Kingdom
Evening all,

Has anyone tried adding Hydrochloric Acid HCL to a central heating system and ran it whilst heating is on? I understand it will react with water especially when hot.

All copper on the system, just looking at a way round replumbing central heating due to severe pipe blockages.

Any recomended methods or a big no no?

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Unless someone can give you written guarantee that it is ok to use that acid on heating systems, stick with known products. Fernox DS40 is good enough to shift almost anything
Why not use a proper flushing chemical, which is designed to do the job and not react with water?

If you have no circulation whatsoever then nothing in the world will shift it
Everything has been tried, including ds40. Plumber mentioned someone using hcl but recommended replumb.
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Hydrochloric acid will not react with water, it will however react with copper to form copper (2) chloride which is soluble in water. I feel you will potentially do more damage than good.
There are two different copper chlorides, one soluble and the other not.

But that's largely irrelevant.

The serious reason to NOT to use HCl in a heating system is because the HCl will react with iron and rust from the inside of the steel rads to form ferric chloride.

Ferric chloride is VERY corrosive to copper and is the traditional etchant used to make copper track printed circuits at home!

As said, if citric acid ( DS40 ) has not cleared the blockage then its unlikely that anything else will shift it. ( unless its contains a lot of lime compounds in which case sulphonic acid ( DS3 ) just possibly might do something ) But most heating system blockages are caused by iron oxides which are dissolved easily in citric acid.


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