I want to save an old water heater if it is possible.
A couple of quick questions…
The water pump I have has a maximum pressure of something like 71 pounds. In testiing the WH to find leaks, should I pump it up to the full 71 pounds ? Leave it for a day or two ???
If it passes the pressure test, but has scale/rust inside, what is the best way to clean that out ?
Replies
If you have any age on the water heater you may be wasting your time. The pressure that you want to test the heater with is fine. A water heater should be able to handle a lot more. To flush out the tank, just connect a hose to it at the top, open the drain down valve at the bottom, and run the water until it runs clear. If you get a lot of rust, it indicates that the tank is getting ready to go. Under those circumstances, I would give up the idea. Good luck.
Thanks for the reply.
=0)
I was hoping maybe there was some common household item that I could add to the water and let it soak before I rinse it out.Something that would maybe help to knock scale and rust loose while I test the heating element after I know it will hold pressure...Salt ?Borax ?Water is at a premium here.So is budget. Ergo, salvaging/repairing a WH rather than just buying one.
A person with no sense of humor about themselves, has no sense at all.
Edited 4/23/2005 7:36 am ET by Luka
Generally, if the deposits are largely hard water deposits, what you need is some sort of weak acid. Vinegar would work, but for the volumes you need it would be better/cheaper to use diluted (about 10:1) muratic acid. (Note: Never add water to concentrated acid. Instead, add the acid, a little at a time, to the water.)Another option would be something like CLR.If the deposits are rust then oxalic acid (available as "wood bleach" at paint stores -- but be sure to read the label to get pure oxalic acid) might loosen things up a bit.Silt is another matter entirely.
I may be stating the obvious here, but adding something like muriatic acid or CLR to a potable water system should not be entered into lightly. Muriatic acid is just that: acid (hydrochloric, I believe). Makes an impressive bomb if you don't leave the water heater vented. Also will generate hydrogen gas (HCl + Fe -> FeCl + H2 (gas)). I used to blow up 2 liter plastic soda bottles with the stuff & aluminum foil.
Not to mention the health effects of you don't get everything out.
But it's correct that good ventillation is important (do the job outside if possible), as is good rinsing of the heater afterwards. From a toxicity point of view, pure (though dilute) HCL is quite harmless. It exists naturally in the stomach. And CLR is advertised for cleaning coffeepots. However, you're creating a witches brew of chemicals, with the lime, rust, and sludge, and some care is definitely advised. It would be wise to not use hot water from the tank for cooking, at least for several weeks after the unit is put back into service.