Announcement

Announcement Module
Collapse
No announcement yet.

Tap into an existing gas line for an extra furnace

Page Title Module
Move Remove Collapse
X
Conversation Detail Module
Collapse
  • Filter
  • Time
  • Show
Clear All
new posts

  • Tap into an existing gas line for an extra furnace

    Ladies and Gentlemen,

    I am in the process of putting an 70,000 btu gas furnace in my garage. I, of course, need to tap into the existing gas line that feeds the furnace, fire place, oven and water heater in my new home.

    I have a set of Wilson dies and taps up to 1" and I have a lathe in the garage to cut the tube, cut the threads and chamfer the end.

    My question is, how in the hell do I tap into the existing main gas line? The existing main line is 1" black pipe. It first Tees off to the water heater, then to the furnace. I need to tap into the main line. Because everything is right hand threaded, it appears that either the first or last piece must be disassembled until I hit the area where I want to tee. Is this correct? Even so, how do you install the last piece of pipe since it must thread into "something" from both ends?

    I assume it is against code, but can I place a Tee where the gas line drops from the main line to go to the furnace?

    Is 1" pipe okay for a 70,000 btu furnace, or is 3/4" sufficient? I haven't purchased anything yet.

    Below is a picture of where I would like to place the tee. This pipe goes from the meter outside into the house. I could always unscrew the gas line from the outside and unscrew it from where it first tees to the water heater in the basement. I assume I would have to cut the pipe so I can unscrew it, yes? Once I cut the threads on the existing pipe, how do I get it back together at the meter since I had to cut it originally?



    Lastly, below is a picture of the existing tee in the main gas line for the furnace. Is tapping into this okay?


  • #2
    Re: Tap into an existing gas line for an extra furnace

    Always check local Codes but you should be able to cut the tee in using a "left to right nipple & coupling".

    http://www.plumbingsupply.com/leftright.html

    More importantly though you need to verify there is an extra 70,000 BTUs of NG available in your system.

    Mark
    "Somewhere a Village is Missing Twelve Idiots!" - Casey Anthony

    I never lost a cent on the jobs I didn't get!

    Comment


    • #3
      Re: Tap into an existing gas line for an extra furnace

      3/4'' is fine since the developed length is minimal.

      unscrewing from the end of the line is usually not practical. unions are not allowed unless at the fixture or meter. but a left and right nipple and coupling is allowed. this is a nipple that is factory threaded with 1 side right hand threads and 1 side left hand threads. same with the coupling.

      works very similar to a turnbuckle

      rick.
      phoebe it is

      Comment


      • #4
        Re: Tap into an existing gas line for an extra furnace

        mark, are you watching me and reworking the time stamps

        rick.
        phoebe it is

        Comment


        • #5
          Re: Tap into an existing gas line for an extra furnace

          Mark,

          I did not know a L/R union exists. This of course means I must find a 1"-11.5 LH die.

          How do I find out whether my gas system can supply another 70,000 btu draw? I assume that all has to do with flow, correct? Would the limit be the size pipe coming from the meter or would it be the meter itself?

          Is 1" sufficient for a 70,000 btu furnace, or can I use 3/4"? I need to run the pipe 14' from the main pipe before it gets to the furnace.

          Comment


          • #6
            Re: Tap into an existing gas line for an extra furnace

            You really will need to check the sizing of the entire system to add anything to it. Here is a calculator I just found online that may help you.

            http://www.engineeringtoolbox.com/na...or-d_1042.html

            Mark
            "Somewhere a Village is Missing Twelve Idiots!" - Casey Anthony

            I never lost a cent on the jobs I didn't get!

            Comment


            • #7
              Re: Tap into an existing gas line for an extra furnace

              Originally posted by PLUMBER RICK View Post
              3/4'' is fine since the developed length is minimal.

              unscrewing from the end of the line is usually not practical. unions are not allowed unless at the fixture or meter. but a left and right nipple and coupling is allowed. this is a nipple that is factory threaded with 1 side right hand threads and 1 side left hand threads. same with the coupling.

              works very similar to a turnbuckle

              rick.
              Rick, I have always been under the impression that a union as long as it is not in a concealed location is OK... Is this a UPC thing or have I been doing it wrong all these years

              Comment


              • #8
                Re: Tap into an existing gas line for an extra furnace

                for some reason they feel that a union can vibrate loose

                rick.
                phoebe it is

                Comment


                • #9
                  Re: Tap into an existing gas line for an extra furnace

                  Sawsall, Hand threader, L.R. coupling and nipple. It's the holidays,
                  Why not help some unemployed Plumber and His family ! You can make a deal to be His Helper. You will learn a lot and make a new friend. Also You will have a good Man down the road if You have a future problem.
                  I can build anything You want , if you draw a picture of it , on the back of a big enough check .

                  Comment


                  • #10
                    Re: Tap into an existing gas line for an extra furnace

                    Originally posted by OkieBill View Post
                    Rick, I have always been under the impression that a union as long as it is not in a concealed location is OK... Is this a UPC thing or have I been doing it wrong all these years
                    Originally posted by PLUMBER RICK View Post
                    for some reason they feel that a union can vibrate loose

                    rick.
                    Actually even a L-R is now illegal in concealed location. A union would be legal but I prefer a L-R for gas. In a concealed location you now have to center-punch a ground joint union to be legal.

                    Mark
                    "Somewhere a Village is Missing Twelve Idiots!" - Casey Anthony

                    I never lost a cent on the jobs I didn't get!

                    Comment


                    • #11
                      Re: Tap into an existing gas line for an extra furnace

                      Rick:

                      >>>unscrewing from the end of the line is usually not practical. unions are not allowed unless at the fixture or meter. but a left and right nipple and coupling is allowed. this is a nipple that is factory threaded with 1 side right hand threads and 1 side left hand threads. same with the coupling.<<<

                      I work in the N. E. area, left and right nipples and couplings were banned back in the day when it was legal to bend gas pipe.

                      We can use unions as long as they are not concealed.

                      Comment


                      • #12
                        Re: Tap into an existing gas line for an extra furnace

                        The left/right coupling is that...a COUPLING...not a mechanical union.

                        It is a threaded coupling with one end LH, one end RH, and a 6" threaded nipple, one end LH and the other RH. Check with local codes to see if they allow this and where.

                        Of course, to get into the existing system, you either have to start at an end and take it all apart back to where you need to be, or just cut the pipe in the middle, and redo using the union or L/R coupling as allowed.

                        Comment


                        • #13
                          Re: Tap into an existing gas line for an extra furnace

                          the no union thing must be a west cost thing ,we can use them also but must be in the open
                          Charlie

                          My seek the peek fundraiser page
                          http://observatory.mountwashington.o...nal&fr_id=1040


                          http://www.mountwashington.org/weather/conditions.php

                          new work pictures 12/09
                          http://public.fotki.com/hvachawk/

                          Comment


                          • #14
                            Re: Tap into an existing gas line for an extra furnace

                            I bought a few fittings at the local plumbing supply store. Surprisingly, Menards was cheaper for everything. Hell, the 1"x1"x3/4" T was almost $1 cheaper at Menards.

                            I plan on cutting the main pipe and removing both pieces of pipe, cutting threads on them and reinstalling them. I plan on using a T, a nipple, a union and then tying that backing into the existing pipe I just cut the threads on. I talked to a plumber who lives in the neighborhood and he said unions are okay so as long as they aren't concealed. Even when I finish the basement, the union will be in the utility room so it will never be covered up.

                            My only concern is screwing up and not having gas until the situation is solved. I guess we'll just have to wait until tomorrow morning to see. Because I am cutting the pipe, will the pipe that connects to the meter be tough to unscrew?

                            Does anyone else, other than Mark, concerned with capacity for a 70,000 btu furnace? It seems as though a lack of capacity would be in the meter restricting flow to the 1" main pipe in the basement. What do you think?

                            Comment


                            • #15
                              Re: Tap into an existing gas line for an extra furnace

                              Ironically, your name is how I answer the phone.


                              J.C.

                              Comment

                              Working...
                              X