Descaling the calorifier

[poiu]

My shower was blocked by scale debris from the hot water pipe, presumably breaking free from inside the calorifier, so I think I should clean it. Digging out the mixer valve for the shower to unblock it was a really fiddly task that I would rather not do again.

Is there a best practice way to do this? I believe phosporic acid is often used for cleaning scale from kettles - would this be a good choice here? What concentration? I couldn't find anything in the archives - has anyone done it?

[UNCIVILIZED]

I haven't done the job you're referring to, but am familar with mineral scale, in some of it's various forms. That, plus one gentle but slow method to get rid of it. And a couple of hypothetical, more agressive methods.

You could start mild, & try heating Distilled water to as high a temp in it as you can. Changing the water frequently.
The idea being, that because distilled water is so "clean" it'll "pull" out/off some of the minerals when you heat it. Which is the reverse of what got you into that fix. Such being, that heating standard water, with a fair mineral content to it, left behind said minerals, when you emptied the unit of hot water each time.

Plan B would be a mild acid. Like say Vinegar (Acetic Acid). I wouldn't heat that, but just let it soak, & see if the vinegar will eat the scale. As, for example, if you drop sea shells or similar (which I think are calcium carbonate) into Vinegar, you can watch them bubble & dissolve.

And as crazy as it sounds, Coca Cola might be another option. As it acts similarly to Vinegar, being an acid itself. Phosphoric I think, actually.

Also, assuming that it's not a vessel used to heat potable water, you might try CLR or orther commercial, household, scale removers. Although what I'd be willing to use on it experimentally, would be based a lot on the replacement price of the item.

As usual, the last resort - Try talking to the company which made it. AKA "the instruction manual" (which you likely can find for it online).

[a64pilot]

My scale is coming from my water tank, it's aluminum and is pretty much covered in calcium.
I installed a water filter just after my water pump and now I don't have to go around cleaning "sand" out of my faucets, etc. anymore.

[poiu]

Originally Posted by a64pilot

My scale is coming from my water tank, it's aluminum and is pretty much covered in calcium.
I installed a water filter just after my water pump and now I don't have to go around cleaning "sand" out of my faucets, etc. anymore.

Sound like you have the same problem. But isn't the water pump after the cold tank? You shouldn't have scale there.

[poiu]

Originally Posted by UNCIVILIZED

I haven't done the job you're referring to, but am familar with mineral scale, in some of it's various forms. That, plus one gentle but slow method to get rid of it. And a couple of hypothetical, more agressive methods.

You could start mild, & try heating Distilled water to as high a temp in it as you can. Changing the water frequently.
The idea being, that because distilled water is so "clean" it'll "pull" out/off some of the minerals when you heat it. Which is the reverse of what got you into that fix. Such being, that heating standard water, with a fair mineral content to it, left behind said minerals, when you emptied the unit of hot water each time.

Plan B would be a mild acid. Like say Vinegar (Acetic Acid). I wouldn't heat that, but just let it soak, & see if the vinegar will eat the scale. As, for example, if you drop sea shells or similar (which I think are calcium carbonate) into Vinegar, you can watch them bubble & dissolve.

And as crazy as it sounds, Coca Cola might be another option. As it acts similarly to Vinegar, being an acid itself. Phosphoric I think, actually.

Also, assuming that it's not a vessel used to heat potable water, you might try CLR or orther commercial, household, scale removers. Although what I'd be willing to use on it experimentally, would be based a lot on the replacement price of the item.

As usual, the last resort - Try talking to the company which made it. AKA "the instruction manual" (which you likely can find for it online).

I should have said, it's a 60 litre non potable tank, so coke won't work on cost grounds. qualifies on non potable though.

Needs to be cheapish really.