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rust in gas pipes

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  • rust in gas pipes

    Hi .. i have recently purchased an old house.. I have noticed that when i open the gas valve to the gas stove (which has not been installed yet), a lot of rust particles comes out of the pipe .. I have opened/closed the valve multiple times but the rust coming out doesn’t seem to get any less .. Does this have anything to do with the fact that the house has been vacant for more than 2 years and no one has used it? is it normal? should i keep running it until the dust stops or is it time for new pipes? .. i have never heard anyone changing gas pipes inside the house .. any suggestions?

  • #2
    The gas itself contains moisture, and sometimes a small amount of sulfur which corrodes the pipes over time. There's a piping arrangement called a sediment trap or "dirt leg" that should minimize the amount of rust & scale that actually makes it out of the piping to the appliance.

    You should probably have your local plumber out to inspect the piping and make sure everything's ok. It's kind of hard to judge these things over the web.

    Comment


    • #3
      you probably might want to disconnect each fixture at the gas cock and replace them with newer gas ball valves. these will hold a proper air test 10psi. at this point you can put an air test on it. if it holds for 10 minutes, then i would use the air pressure to flush out the remaining rust. a compressor should be able to supply the necessary volume of air. keep in mind, only gas or air can be put into a gas system. regular house gas pressure is approx. 1/3 of a pound or 7'' water column.

      if it doesn't hold a test, use a spray bottle with 50/50 soap and water to spray all exposed joints and check for bubbles with air in the line. keep in mind the older style gas cocks probably will not hold a 10psi test.

      rick.

      rick.
      phoebe it is

      Comment


      • #4
        Switchex,

        I would suggest:

        1) Removing the gas cocks and capping the ends of the lines with black or galvanized caps for testing purposes.

        2) Disconnecting the main from the meter and installing a tee with a 15psi test gauge.

        3) Charge the line with 10psi of nitrogen. The problem with using an air compressor is that it may inject more moisture into your piping, which if you have rust, is your problem now. You can rent bottles of nitrogen and a regulator at welding supply shops.

        4) If it holds for 10 minutes go to step 5, if it doesn't follow Rick's advice.

        5) Release the pressure from the piping.

        6) Remove one cap. Blow nitrogen through the piping until there is no rust.

        7) Recap the pipe and remove another. Blow out each gas outlet individually.

        8) If you are still getting rust consider a repipe.

        If the house has been sitting for two years some rust may be normal. An excessive amount may cause problems by clogging regulators and the orifices of your fixtures.
        the dog

        Comment


        • #5
          Originally posted by plumbdog10
          Switchex,

          I would suggest:

          1) Removing the gas cocks and capping the ends of the lines with black or galvanized caps for testing purposes.

          2) Disconnecting the main from the meter and installing a tee with a 15psi test gauge.

          3) Charge the line with 10psi of nitrogen. The problem with using an air compressor is that it may inject more moisture into your piping, which if you have rust, is your problem now. You can rent bottles of nitrogen and a regulator at welding supply shops.

          4) If it holds for 10 minutes go to step 5, if it doesn't follow Rick's advice.

          5) Release the pressure from the piping.

          6) Remove one cap. Blow nitrogen through the piping until there is no rust.

          7) Recap the pipe and remove another. Blow out each gas outlet individually.

          8) If you are still getting rust consider a repipe.

          If the house has been sitting for two years some rust may be normal. An excessive amount may cause problems by clogging regulators and the orifices of your fixtures.
          dog is back in the house

          dog, glad you came back home. i think you'll find a couple of interesting new posters here

          mark checks in every couple of weeks too.

          rick.
          phoebe it is

          Comment


          • #6
            I sort of had the idea in my mind about blowing the rust out of the pipe using air .. except that I was thinking of using my shop vac and retrofit the hose, attach it to the main and blow air into pipe (Don't laugh! :-) .. i guess that was pretty stupid

            Anyway, Here are a few (probably stupid) questions.

            1- What is the point of the 10 min test? Is it to see if there is a leak some place?

            2- Since the pipes are old, just wondering how hard it would be to disconnect the main from the meter.

            3- So i can rent the nitrogen from a welding supply? How large are the nitrogen cylinders and how much do i need? Any danger in using them?


            4 - Is there a name to this procedure, so that I can call a pro for pricing? How much do you think it would cost?


            5- what is the life of these pipes anyway? never heard of an old house exploding becasue of old pipes!

            Thanks again.

            Comment


            • #7
              #5 - http://www.sj-r.com/extras/galleries...sp?gallery=216

              Switchex, I'm not trying to insult or discourage you, but gas piping is probably not a do-it-yourself project. Have another look at the last photo in the above gallery.

              If you want to spray some soapy water on the joints and check for leaks, that's fine, but you can cause some damage pressurizing that system if you don't follow the procedures exactly.

              Comment


              • #8
                thanks ralph .. i needed to see that picture to remind myself of my limitations .. if i do decide on doing the job, i make sure to hire a pro for final hookup to the meter and inspection. thanks again.

                Comment


                • #9
                  Dogs' procedure should work OK.
                  I would add when blowing down the line(s) to start at the closest point to your N2 bottle and blow down there first. That way you don't push junk through pipe you don't have to. You could use a clean white rag placed over the end of the pipe to see when you are getting it clean (once the big pieces are out and it is just the fines it can be tough to see).

                  Be careful with an N2 bottle, lots of pressure there, handle with care and don't transport with the cap off. Many people do it but the proper and SAFE way is to remove the regulator and install the cap when moving compressed gas cylinders. If you have never seen one of those safety films where the bottle takes off like a rocket and punches through a block wall you can't appreciate what one of these things can do if you let all the gas out at once


                  "never heard of an old house exploding because of old pipes!"

                  That's because nobody lives to tell the story
                  ---------------
                  Light is faster than sound. That's why some people seem really bright until you hear them speak.
                  ---------------
                  “If I had my life to live over again, I'd be a plumber.” - Albert Einstein
                  ---------
                  "Its a table saw.... Do you know where your fingers are?"
                  ---------
                  sigpic http://www.helmetstohardhats.com/

                  Comment


                  • #10
                    Originally posted by Bob D.
                    Dogs' procedure should work OK.
                    I would add when blowing down the line(s) to start at the closest point to your N2 bottle and blow down there first. That way you don't push junk through pipe you don't have to. You could use a clean white rag placed over the end of the pipe to see when you are getting it clean (once the big pieces are out and it is just the fines it can be tough to see).

                    Be careful with an N2 bottle, lots of pressure there, handle with care and don't transport with the cap off. Many people do it but the proper and SAFE way is to remove the regulator and install the cap when moving compressed gas cylinders. If you have never seen one of those safety films where the bottle takes off like a rocket and punches through a block wall you can't appreciate what one of these things can do if you let all the gas out at once


                    "never heard of an old house exploding because of old pipes!"

                    That's because nobody lives to tell the story

                    Bob D. is talking sense, here. Important saftey factors. I have, as of late, attempted to be a kinder and more understanding Dog to homeowners. It isn't working. I basically grew up with construction, and I work with construction professionals. When I give advice to homeowners I often forget that what comes second nature to those of us in these fields are very much new to the handy homeowner. That is why I often give advice such as "Hire a plumber".

                    To tell you the truth, Switchex, I would consider hiring a plumber. Let him test the lines for leaks and make a call on a repipe. Ralphtheplumber (as a hugh fan of "The Honeymooners" I love the handle) is correct in saying that a gas repipe is beyond a homeowner project.

                    Don't save money over saftey.
                    the dog

                    Comment


                    • #11
                      thanks all .. Ok .. i'll promise to hire a pro for the job .. i am comfortable with all phases of construction as well and have done plumbing before .. but i guess i should not be working with gas pipes .. at least I now have an idea what to expect when i call a plumber .. ty.

                      Comment


                      • #12
                        I would agree that it would be a good idea to call a plumber, but if you were to do it I would use compressed air. i think the nitrogen is a little bit of overkill considering you are only going to have the air in the pipes for less than an hour. Also if you use air then you can really blow the lines out as with nitrogen you have to be careful as this will displace oxygen and possible cause a problem to your health.

                        Comment


                        • #13
                          The advantages of using nitrogen are it is clean, inert, and dry.
                          You can get clean, dry compressed air but not out of the run-of-the-mill home shop or jobsite air compressor. Since it is already established (or at least is the general consensus of the respondents) that you have a moisture problem then pumping moisture laden air in is not going to help.

                          I totally agree with the Dogs' statement:

                          Don't save money over safety.


                          It always cheaper to "Do It Right The First Time". If that means you have to hire someone else then so be it. At least every time you leave the house you won't be worrying if it will be standing when you get home.
                          Last edited by Bob D.; 10-05-2006, 05:58 PM.
                          ---------------
                          Light is faster than sound. That's why some people seem really bright until you hear them speak.
                          ---------------
                          “If I had my life to live over again, I'd be a plumber.” - Albert Einstein
                          ---------
                          "Its a table saw.... Do you know where your fingers are?"
                          ---------
                          sigpic http://www.helmetstohardhats.com/

                          Comment


                          • #14
                            Bob i am not arguing that a diyer should not touch natural gas!

                            I am only saying that if it was my house i would hook my air compressor up and blow the system out that way because i do not think that this will in anyway cause further problems.

                            Bob everytime you do a gas instal do you pressure test it with nitrogen or do you use your air compressor?
                            If it was your house would you buy nitrogen or would you use your air compressor?

                            Comment


                            • #15
                              Plumber Jay,

                              Stick around and listen, you might,..........just might, learn something.
                              the dog

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