DavidTu
Member
We just did our pressure test for the DWV system. It is a two-story house w/ basement and there is a lot of 4" cast iron. We filled up through the roof w/ water and it was holding for over 2 hours awaiting the inspector. Anyway, by the time we were done he noticed a coupling at the bottom of the stack was leaking. Didn't seem too concerned about it and didn't flag it on the inspection, which he signed off on. However, when I looked more carefully (we were using a sausage and so a little water at the base was expected from "sausage drip") the coupling was indeed leaking. I tightened it up again w/ the 60 lb torque wrench and it stopped. However, I noticed that three couplings above also had some leakage.
So, now I am wondering what is going on. Again, it's all sections of straight fittings here, all the couplings were originally tightened to 60 lbs. We have run the test twice before without any leakage noticed. The stack was assembled a long time ago... as much as a year prior! Trouble is that part of it is now framed-in a bit and cannot easily access with the torque wrench. I am wondering if the couplings just relax a bit over time. It always seems that the torque wrench applied to any previously tightened coupling will tighten it up a bit before the wrench clicks.
So if we have a water column through the roof w/ a lot of 4" for 2 hours time there is a lot of pressure. I can make the couplings accessible and tighten them up, if need be... but is there any point? Are they not just gonig to relax again enough to allow this high pressure test to leak again... if not immediately then in a year's time? I really do think these connections are very clean and the couplings in good condition. Am I justified in thinking this is just due to time and in actual usage we will NOT see any leakage, but only with the high pressure of the test, after the stack is sitting so long? Or is that nonsense?
Thanks.
So, now I am wondering what is going on. Again, it's all sections of straight fittings here, all the couplings were originally tightened to 60 lbs. We have run the test twice before without any leakage noticed. The stack was assembled a long time ago... as much as a year prior! Trouble is that part of it is now framed-in a bit and cannot easily access with the torque wrench. I am wondering if the couplings just relax a bit over time. It always seems that the torque wrench applied to any previously tightened coupling will tighten it up a bit before the wrench clicks.
So if we have a water column through the roof w/ a lot of 4" for 2 hours time there is a lot of pressure. I can make the couplings accessible and tighten them up, if need be... but is there any point? Are they not just gonig to relax again enough to allow this high pressure test to leak again... if not immediately then in a year's time? I really do think these connections are very clean and the couplings in good condition. Am I justified in thinking this is just due to time and in actual usage we will NOT see any leakage, but only with the high pressure of the test, after the stack is sitting so long? Or is that nonsense?
Thanks.