Next steps before replacing hot supply line

Discussion in 'Plumbing Forum, Professional & DIY Advice' started by Viktoria, Jul 1, 2014.

  1. Viktoria

    Viktoria New Member

    I'm a first time poster, but a lurker for the last several months. I read a lot on this site before attempting to replace a hot water heater that was failing. I had enough time to really prepare, and I'm happy to say it went pretty well.

    As to be expected, the very old galvanized hot line sprung a leak at a shutoff valve, about 24" from the heater, from the jarring/movement of the install. I knew it was very possible with such old pipes, and handled this too, by cutting the pipe and replacing. When installing the tank I was pretty impressed with how rusty and corroded the hot line was. The cold line was perfectly clear. When I cut the hot line the threaded end that fed into the shutoff valve was so disintegrated, it just fell out.

    About a 4 or 5 days after the pipe repair, I went to take a shower and there was just barely a flow. I'm pretty convinced it's rust that was knocked lose from my work and is blocking the line. (Bathroom is second floor)

    The bathroom sink however, has fine pressure. I assumed there must be powerful corrosion in the horizontal run between the sink and the tub.

    The kitchen sink (first floor) is fed from a different branch off of the same trunk--pressure is fine.

    So, now I am doing my research to prepare to replace the hot line to the tub. I'm spending a lot of time mapping the current system (one bathroom, one kitchen, small house).

    I'm planning on cutting through the drywall in the bedroom behind the bathroom wall to do some more fact finding.

    I was wondering if there is any possibility that the corrosion has lodged in the mixing bath/shower valve, and is restricting the flow? I don't know enough about the mechanics of the valve to know if this is likely, and thought I had better look into that possibility before I start cutting drywall.

    The valve itself is new--I replaced it last summer.

    Thank you for your input.
  2. Terry

    Terry Administrator Staff Member

    Bothell, Washington
    You can pull the cartridge and try that first. You may get lucky.
    In any old system, the hot goes bad first.
    And any pipe that threads into brass is going to go bad first. At some point, you will be replacing the hot and cold. When you open a wall up, you might as well get it all. Whatever is left, becomes a job for an other day.
  3. Viktoria

    Viktoria New Member

    I am cautiously excited to replace it all--there is some really wacky stuff going on, a couple reversed hot and cold lines and weird routing--convoluted even.

    I have some time on my hands this summer, but I like to do these kinds of things when the kids are away so I can concentrate. I know I have some nice blocks of time coming up.

    I will pull the cartridge and investigate. I will look into getting the proper tool to pull it because when we pulled it last summer, I had a friends help, but no tool, and it was hairy.
  4. Viktoria

    Viktoria New Member

    Brass to galvanized--no dielectric fitting--it didn't even occur to me that was an issue--and I learned about electrolysis while reading about sacrificial anodes HERE.

    It takes a while to UNDERSTAND what I'm looking at. That is why I go slow--I would have failed a pop quiz on why those threads were so corroded.
  5. hj

    hj Moderator & Master Plumber Staff Member

    Cave Creek, Arizona
    What is the make and model of your valve? It could be a very simple fix depending on your reply.
  6. Viktoria

    Viktoria New Member

    Unfortunately, i don't know how to easily tell the model--and I haven't pulled it yet.


    It's Moen, and when I went to the plumbing supply last summer with the original, he had a replacement.

    Attached Files:

    Last edited by a moderator: Jul 1, 2014
  7. Viktoria

    Viktoria New Member

    I pulled the cartridge.

    About 5 tiny shreds of black rubber came out with the cartridge.

    While the cartridge was out, I went to the basement and opened the hot water shutoff a smidge, went up and checked the flow, it was slow but MUCH better than from the spout. I kept going down and opening it a bit at a time until it was open full bore. This is what the flow looked like:
    Pitiful, I know, but i was happy to see this much because there was just a poor drizzle coming out before.

    The cartridge looked weird--like the holes weren't all properly aligned with each other. I rinsed it and blew air into it And re-installed it and the trim, turned on the water, and was amazed that the flow was suddenly nearly powerful--except it was cold--I put it in upside down.

    When I bought the cartridge last summer (almost a year ago exactly) the man at THE Faucet Shop (Chicago) said the Moen logo on the side of the cartridge should be on the right side when putting it in. If I do this the cold comes out where hot should. When I reversed it the hot water comes out when the dial is turned all the way to the left. Either the pipes are reversed or the nice man at Faucet Shop was having fun with me.

    Anyway, the cartridge is in, and the flow is better--now when I run the hot water in the tub and sink both, the sink suffers dramatically. Before it was very strong, even while running the tub.

    My thoughts are:

    1. The cartridge is not working as well as it should (the original was brass, this replacement is plastic).

    2. Galvanized needs to come out ASAP.

    3. I'm having trouble deciding copper or PEX.

    Since my original post I feel less confident that I know the direction I should take. PEX seemed like a good direction to move in, seems like a lower bar to competency than sweating pipes, and less costly materials, good for a novice who will likely make mistakes. I'm willing to learn to do both and practice first. I would very much like to do as much of this myself as possible.

    I live in Chicago--I'm starting to think my original decision on PEX foolhardy. I'm concerned I could get into trouble with my homeowners insurance or otherwise because of the PEX.

    I believe it's safe and a great option for someone in my position--but I would be flouting city code.

    How do I make this decision. I am really getting excited thinking about a hot, forceful shower, and rinsing the shampoo out of my hair in less than 10 minutes. image.jpg

    (Yes, as a matter of fact I am very much looking forward to renovating my bathroom. Pipes first.)

    edited for spelling.
    Last edited by a moderator: Jul 6, 2014
  8. Terry

    Terry Administrator Staff Member

    Bothell, Washington
    With the Moen Posi-Temp, the cold should come on first, and get warmer as you rotate counter-clockwise.
    You may need to reverse the cartridge if that isn't so. No harm in that, as many times in back to back installs the pipes may be reversed.

    Galvanized pipes over time don't carry enough water to the fixtures.
    Copper is always a good choice.
    I didn't know that Chicago didn't allow PEX. Seems kind of old school, but you still have the copper option.
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