Copper air test questions

Discussion in 'Plumbing Forum, Professional & DIY Advice, Tips & ' started by bsperr, Jul 6, 2010.

  1. bsperr

    bsperr Member

    Messages:
    74
    Location:
    Athens, GA
    I finished soldering the supply lines for my kitchen, laundry room, and utility sink, and I am running an air test to see if there are any leaks. I figured I'd do an air test rather than just hooking up the water because I might have a better chance of getting a bad joint to take new solder if it hasn't gotten wet. I looped the supply lines and filled it up with 100psi of air. From looking at the pressure gauge, it looks like I've lost around 10psi after an hour. I checked the gauge itself for an easy leak to fix, but no such luck. I haven't checked all of the joints yet, but I had a few questions to make sure I'm doing this right before proceeding.

    I'm testing against the closed valves of my washing machine and ice maker supply boxes. Is this correct, or should I open the valves and cap them? These valves all have built in hammer arrestors. Would this affect the results? I soldered my supply lines directly to the washing machine and ice maker boxes. Is it really easy to apply too much heat to these joints to affect the seal of the valves? Thanks for your help.
  2. Terry

    Terry Administrator Staff Member

    Messages:
    14,776
    Location:
    Bothell, Washington
    Just make up some liquid soap and water is a spray bottle and hit the joints with it.
    If it makes bubbles you have a leak. If not, you should be good.
  3. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    26,263
    Location:
    Cave Creek, Arizona
    Your leaks, if any, are not likely to be in the valves. If there were no leaks, the pressure would remain static for days, or even weeks. The only variation would be as the water cools or warms up.
  4. bsperr

    bsperr Member

    Messages:
    74
    Location:
    Athens, GA
    I've gone over all my joints with some Big Blu solution, but I still don't see an obvious leak. I'm going to add some solder to a joint that looks suspect, but if that doesn't work I'll have to hook up the water so I'll know for sure. Are there any other tips for finding small leaks?
  5. bsperr

    bsperr Member

    Messages:
    74
    Location:
    Athens, GA
    I checked my valves just in case and found my leak in the hot water supply of my washing machine box. Is there any way this can be fixed, or do I need to replace the whole box?

    Attached Files:

  6. johnjh2o1

    johnjh2o1 Plumbing Contractor for 49 years

    Messages:
    1,141
    Location:
    South*East
    You can replace the valve. Welcome to the plumbing world. We have a saying ( we don't have leaks we just buy them)

    John
  7. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    26,263
    Location:
    Cave Creek, Arizona
    Sorry to say this, but I would NEVER have installed a box that was that "tight" around the valves. Where is the leak? In the valves or the piping to the valve?
  8. johnjh2o1

    johnjh2o1 Plumbing Contractor for 49 years

    Messages:
    1,141
    Location:
    South*East
    I see bubbles coming from the hot valve.

    John
  9. bsperr

    bsperr Member

    Messages:
    74
    Location:
    Athens, GA
    I like the design of the box because it puts the supply and drain in two different boxes, and it was cheap, but I didn't think about needing to service it (which is probably impossible). The leak is in the valve itself. I don't know if it was a defect or if I overheated it, but I was wondering if there's any way to restore the seal of the valve now that it's been broken. I imagine I'll probably have to replace the box though.
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