The Tank › Installing new ball valve, brass, PVC, or Galv ?
- April 24, 2005 at 1:30 pm #3656Guest
I was installing my new heater yesterday and saw your advice to install a new ball valve for the drain. That is good advice!! I couldn’t believe what I saw when I looked into the white plastic stock valve, there is about a 1/8″ hole in there when it is open!! The issue I have is that my new heater has very thick insulation, about 3″. It is a GE/Rheem electric tall 50 Gal with a energy factor of .94. I am guessing it is R-24? Anyway, your ball valve setup appears to use a dielectric nipple (plastic lined). I needed a 4″ nipple. So my choice was plain galvanized, brass, or schedule 80 (gray) PVC. And BTW I am using a white PVC ball valve. The guy at Home Depot said there would not be any dielectric problems with brass threaded into the steel tank. Is that right? Brass is 80% copper isn’t it? Anyway I went with the Schedule 80. Was that the best choice?
MikeApril 24, 2005 at 10:34 pm #3663Randy SchuylerKeymaster
That might work, Mike, but we’ve found PVC to be somewhat fragile and somewhat prone to fail in heat conditions. We couldn’t use it here because it would violate local code. I’d lean toward a brass nipple and a brass ball valve.
Randy SchuylerApril 25, 2005 at 11:47 am #3667Guest
Doesn’t brass react with iron? Can I find a plastic lined 4″ nipple somewhere?April 25, 2005 at 12:17 pm #3668Larry WeingartenParticipant
Hello: Brass does react with iron, but fortunately, less so in the presence of an anode. As far as I know, lined steel nipples come in almost two inches, then three and six inch lengths. It would be useful to see one made four inches!
Yours, LarryMay 20, 2005 at 8:13 pm #3734ThorsgarParticipant
First, PVC is not rated for hot water. Second Brass does NOT react with iron it is the breaker of di-lectric reaction.May 21, 2005 at 3:28 am #3738Randy SchuylerKeymaster
The Tank is a place where everyone can express an opinion. Ours is that brass CAN cause corrosion of steel when the two are placed together in water. That’s based on considerable experience in the field. But brass nipples for tank use are still better than galvanized because they retain their structural integrity and don’t clog with rust. Best of all is plastic-lined steel, which can’t react with tank steel and whose plastic lining prevents reaction with dissimilar metals and clogging.
Randy SchuylerMay 23, 2005 at 1:41 pm #3743Larry WeingartenParticipant
Hello: Regarding brass and steel. The reaction between them increases as the electrolite, (water) is harder or more conductive. In areas with naturally soft water, brass will do essentially no damage to steel. In agressive water, this is not so. In books on corrosion the “galvanic scale” is described. It is a ranking of metals based on their desire to corrode, when in contact with each other. One always corrodes to protect the other. The “noble” metal (cathode) is protected. The further apart on the scale, the more voltage is generated between metals and the faster the “anode” corrodes. Sodium is near the bottom of the list while platinum is towards the top. Copper and brass are side by side, a little ways above steel, which is above magnesium. Magnesium protects steel, which protects brass, which protects platinum, etc. Look up the “National Association of Corrosion Engineers” for more info. Hope that helps.
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