hot water tank flush

[Protagonist]

Originally Posted by HiJoeSilver

Explanation below.

The type found deposited on the heating elements of water heaters has a main component of calcium carbonate. Hard water contains calcium (and often magnesium) bicarbonate or similar ions. Calcium salts, such as calcium bicarbonate and calcium carbonate are both more soluble in hot water than cold water. Thus, heating water does not cause calcium carbonate to precipitate per se. However, there is an equilibrium between dissolved calcium bicarbonate and dissolved calcium carbonate:

Ca2+ + 2HCO3− ⇋ Ca2+ + CO32− + CO2 + H2O

where the equilibrium is driven by the carbonate/bicarbonate, not the calcium. Note that the CO2 is dissolved in the water.

There is also an equilibrium of carbon dioxide between dissolved in water (dis) and the gaseous state (g): CO2(dis) ⇋ CO2(g)

The equilibrium of CO2 also moves to the right towards gaseous CO2 when the water temperature rises. When water that contains dissolved calcium carbonate is warmed, CO2 is removed from the water as gas causing the equilibrium of bicarbonate and carbonate to shift to the right, increasing the concentration of dissolved carbonate. As the concentration of carbonate increases, calcium carbonate precipitates as the salt: Ca2+ + CO32− ⇋ CaCO3.

As new cold water with dissolved calcium carbonate/bicarbonate is added and heated, CO2 gas is removed, carbonate concentration increases, and more calcium carbonate precipitates.

That's why I'm an engineer and not a chemist…

[HiJoeSilver]

Originally Posted by Protagonist

That's why I'm an engineer and not a chemist…

Me too but I stayed at a holiday inn express last night.

I'm usually the precipitate pointing out the problem, so I guess they also makes me part of the problem as well.

[cwf]

Here is result of a vinegar-water 50/50 concentration and 3 hours heating on electric.
http://a68.tinypic.com/21j4wo5.jpg

[pcskier]

Once a year should be plenty. I prefer to do it in the fall when winterizing. One less thing to do in the spring. I use the heated vinegar overnight method, then flush with the Camco wand. Gets a good amount of crud out. How often you use the trailer and hot water obviously has an impact, as well as how hard the water is where you go. Here in the West, most water sources are fairly hard. I do use an external filter, not sure if that impacts hardness much but I do notice I don't get deposits in my sinks when they get wet so it must help some.

[Smathers]

I’m looking for a solution to soak lime scale out of a water pressure regulator from a 2016 FC. currently have a temporary loan.