Drains blocked with limescale

ro_ava

Hello all
My bathroom drain is blocked up. The house had been vacant for 10 years before we moved in so I can only assume that the limescale that is blocking it is due to still water in the pipes(?) We had dynorod out to look at it and they removed the blockage advising us that there was a large amount of limescale within the pipe which we would need to gradually remove using something like zoflora everyday. I will admit I haven't been vigilant in using zoflora everyday but I have been putting it down there, nevertheless it has started to block up again.

How can I get rid of the limescale? I have alsotried soda crystals and boiling water but that made no difference at all.

Many thanks 

tacpot12

I've had success with Harpic Limescale Remover. I think this will work much more quickly than Zoflora. 
I'd suggest that you block the pipe at a point where you know it doesn't have any limescale, and then fill it with a couple of bottles of Harpic Limescale Remover diluted with about the same amount of warm water. 

Ectophile

You need something acidic to dissolve limescale.  Most of the drain unblockers are alkaline, which makes them good at dissolving food waste, hair and the like, but no good for limescale.

Carrot007

Ectophile said:

You need something acidic to dissolve limescale.  Most of the drain unblockers are alkaline, which makes them good at dissolving food waste, hair and the like, but no good for limescale.

Pretty much this. Go to the local DIY place and get a tub of "patio (or brick) cleaner". This is acid. Poor some some down and leave for an hour and then flush with lots of hot water (though unlikely to cause any issue unless it comes into contatc with metal).

grumbler

ro_ava said:

I can only assume that the limescale that is blocking it is due to still water in the pipes(?)

The amount of limescale in STILL water is minuscule. The water has to run for it to build up.

Emmia

We had a drain blocked with limescale, and it was basically water jetted out by a drain company - it took 2 visits and several hours - some of the pieces they dislodged and pulled out out were forearm sized.

Jeepers_Creepers

Hi Ro.

"Bathroom drain" - what do you mean? The toilet? Basin? Bath? All?

If it's only the 'small' items with 11/4 and11/2" waste pipes, then can you get to the ends of these before they join the 4" soil stack? Or, if it's 'all', then where is the nearest manhole cover to the bathroom?

As said above, if you can access the end of the pipe where the blockage is located, and cap that off, then anything you then add to dissolve the limescale will have FAR better results as it won't be constantly draining away.

'Brick cleaner', as Carrot says, is nicely powerful - something 10% hydrochloric acid? I don't think it would attack vitreous sewer pipes (tho' maybe the cement used to join them?), but you may wish to check before considering it. If your pipes are plastic, you are good to go...

stuart45

You can get even stronger than 10%. Some of the stuff used on site was over 20%. It won't attack the vitrified pipes or the salt glazed ones, but the salt glazed pipes had either lime or cement mortar joints. Acid does break down lime and OPC, but the joints are usually a strong mix so it would take quite a while to get through them.
However it's good you mentioned the potential issue, as it's best not to weaken the joints.

Jeepers_Creepers

All I know is, I bought some recently to clean out my P2P boiler exchanger - and it didn't 'alf foam up when it over-spilt on to the bricks I'd placed underneath... They look otherwise unharmed, tho'

stuart45

It normally foams up when it's attacking something. Clay bricks should be fine, but there are bricks made from concrete and also sand/lime. It will go for these, although would take a lot to destroy them. When cleaning brickwork down it will attack the joints, so it's always best to soak the wall down first so it stays mainly on the surface. 
Could be the bricks under your boiler had a film of sand /cement on them.
The really strong still is quite nasty. We normally used to dilute a bit. Test it out on the labourers wrists. Should hurt them a bit, without taking their skin off.

Alfrescodave

Several litres of **** Cola down the drain should be acidic enough to shift any limescale deposits.   Best place to put the stuff in my opinion