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Rusty substance

Nikolai Member Posts: 31
Happy New Year Everyone!
Had a customer walk in the other day with a problem that I thought I would run by you all.

Customer has a JW hot water heater installed and comes off of his hot line with copper, then 6" off of that it goes through a Dahl brass ball valve. A year and a half after the tank was installed flow through this hot line became very restricted. Ended up that he opened up the line off of the tank and found that inside the ball valve there was a formation of a hard rusty(almost glossy) substance restricting flow. He explained the the substance was very hard and had to chip it away. Rust on a brass fitting?...I don't think so.
After it was cleaned the same thing happened again only after a few months.
There are no dielectric uniions installed on the tank and I am thinking that this may be an electrolysis issue. What do you guys think?


  • Larry Weingarten
    Larry Weingarten Member Posts: 3,230
    hard build up

    Hello: I'm not really clear on the set up you have, but if the valve that is becoming blocked is on a short line, close to the tank, it's possible the anode in the heater "sees" the noble metal and is attempting to protect it. I'd put a plastic lined nipple in the tank, then a copper flex line and then your ball valve. That gives you a dielectric and puts distance between the anode and noble metals. Hope that helps.

    Yours, Larry
  • Weezbo
    Weezbo Member Posts: 6,232
    your buddy is delusional,brass doesnt rust.

    his problem stems from what hes putting into the system not the "visual"effects. trust me God doesnt suspend the law of Physics to "get even" with people by attacking thier water systems.
  • Nikolai
    Nikolai Member Posts: 31

    What exactly is the purpose of the Anode?
  • Constantin
    Constantin Member Posts: 3,796
    To prevent corrosion

    Anodes make the tanks last longer. Otherwise, galvanic interaction would eat up the nipples and so on in no time. IIRC, the best (most reactive) anodes are made of magnesium, with Al being the standard choice.

    Anodes become particularly important in systems with a high degree of salts present, like in softened water. The greater the diluted salt content, the more aggressively the water attacks the dissimilar metals.
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