On 01/08/2018 11:53, newshound wrote:
On 01/08/2018 00:53, John Rumm wrote:
On 31/07/2018 21:38, wrote:
The flow to my bath has dwindled over the years, it's a conventional
vented cylinder and 3/4" copper pipes, is there likely to be any
benefit in dosing the cold water tank with sulphamic acid and then
recirculating through the bath tap connection with a pump?

A tub of fernox DS3 will make enough gallons to fill the tank and the
cistern, so yup recirculating with a pump for a few hours should do
the trick. Keep the immersion on for better performance (but don't let
the cistern get too hot if its plastic - they can go droopy if not
well supported)


My first house had a rivetted galvanised hot water tank, and many metres
of iron pipe getting on for 2 inches OD in the gravity DHW system which
must, once upon a time, have gone to a coal stove in the scullery. Some
of this pipework was almost completely blocked with scale, there must
have been kilogrammes of it in the whole system. My recollection is that
while this particular type of scale dissolves readily enough in
hydrochloric acid, the dissolution rate is quite slow in weak acids. So
while I agree with the theory of your analysis, I'd worry how well it
would work in practice. Heating should help.

Yup heating helps greatly...

The fernox instructions for a manual descale, suggest a minimum of 4
hours with the temp between 50 to 60 deg C.

You may get faster results with a continous recirculation system.

https://fernox.com/cpt_downloads/des...stem-manually/



--
Cheers,

John.

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