New shower plumbing... final loose ends.

I'm almost ready to do the last part of the carpentry for the tub enclosure to get it ready for the new tub itself later this week. However, I'm feeling like it might be a REALLY good idea to test whether it's watertight before going any further , while I can still get at it and make changes fairly easily (well, compared to ripping out new studs and Hardiebacker) if it leaks.

What I'm planning:

1. cap off the nipples for the shower head and tub filler with thread tape and PVC caps.

2. shut the valve leading to the water heater so cold water can't flow into it.

3. turn the mixer on the new shower to 'cold', and the pressure to 'closed'.

3. install a temporary Sharkbite valve on the cold water supply "upstream" from the new shower, and make sure it's closed.

4. Open the main valve outside.

5. slowly open the temporary valve on the cold water line. Shut it off instantly at the slightest hint of leakage or spray. Because the water flow at the shower valve itself is shut off, only the cold water line between the shower mixer and temporary sharkbite valve should have water at this point.

6. slowly open the shower valve. Since it's turned all the way to 'cold', this should allow water to flow through the copper vertical pipes. Once again, shut the valve instantly at the first hint of spraying or leakage.

7. slowly turn the temporature valve from 'cold' to 'warm'. At this point, since the hot water line is empty, water should flow backwards through the shower mixer... in from cold, out to hot, and slowly pressurize the new hot water line.

8. If it made it this far without leaks, close the shower's valve, and turn it to 'cold'. Turn off the water outside, but leave the temporary valve in the bathroom open. Turn on a sink downstairs (warm) to drain the pipes, and open up the water heater's inlet valve too. Flush the toilet, and turn on every other sink in the house to drain as much water as possible.

9. Turn off the sinks when water ceases to flow. Close the temporary sharkbite valve on the cold water line in the bathroom. Close the water heater's intake valve. Open the main water valve outside.

10. Grab a bucket. Remove the temporary cap from the shower nipple. Slowly open the temporary cold-water intake valve in the bathroom to re-pressurize the line.

11. Hold the bucket under the showerhead's nipple, and slowly ease the valve open on the shower's mixer. So far, so good?

12. Uncap the the filler spout's nipple. Screw on the filler spout. Put the bucket underneath it. Recap the showerhead nipple.

13. Slowly ease the valve open again. Verify that it still works without leaks.

14. Close the shower valve. Open the water heater's intake valve. Let the water heater fill. Keep the breakers turned off so the water won't heat up. Close the temporary cold-water intake in the bathroom.

15. re-open the shower valve with the temperature on 'cold'... after emptying the pipe, the water should stop.

16. slowly turn the temperature valve from 'cold' to 'hot'. Water is now flowing in the right direction from tank to shower.

17. Close the shower valve, turn temperature valve to 'warm'. Open the temporary valve leading to the bathroom. Both hot and cold supply lines should now be pressurized normally.

18. Slowly open the shower valve, then adjust the temperature from cold to warm to hot and back. Verify that there are still no leaks.

19. Re-cap the tub spout. Leave the shower valve closed. Spend the rest of the day working in the bathroom... ever-vigilant for leaks. Turn off the main supply to the house whenever I'm not in the bathroom (or at least at the house actively using water elsewhere).

Does this sound like a reasonable plan?

On the slightly grim side... is it safe to assume that plumbing is subject to "infant mortality", just like computer hardware? IE, if it's going to fail within the next 3-5 years, it will probably fail within the first N days... and if it makes it to day N+1 without visible leaks or failure, I can sleep at night knowing it's probably going to be at least as good & dependable as the old PB plumbing it replaced? If so...

a) How many days should I wait before feeling like it's safe to leave the water line open when I'm not home?

b) How many days should I wait before closing up the wall once and for all?

test

The real question is, "How many days is it going to take to follow all those steps?" You have turned a simple 2 minute process into a research paper. WHY would you install a temporary valve? TEMPORARY means it will be removed, and then you have to make two new connection to fill the void where it was. That means you have to perform most of the process again to test those connections. Here is what you do;
1. Look at all the connections to be sure you actually soldered them all.
2. turn on the meter, with someone in the room in case of a major mistake. Ideally with their cell phone connected to yours.
3. If there is a "major mistake" they will shout to you or use their cell phone to tell you to shut it off.
3. Check the piping.
4. Wait 30 minutes and then close the walls.

Well, there's one important detail motivating the temporary valve... I live by myself, and my friends live ~25-40 minutes away. I had a hard enough time getting one of 'em to drive up last Saturday to help me move the old tub out and carry the new tub upstairs. With the valve, I can safely test it out myself by ensuring that water never gets into the pipes unless I'm physically there, in the room ready to shut it off in an instant if Something Goes Terribly Wrong(tm).

Also, they're not soldered... they're Gatorbite'd (Gatorbitten?)

Is 30 minutes really long enough to confidently discern whether they're secure, leak-free, and likely to stay that way for at least a few years?

joints

In that case just turn the valve on so that a modicum of water is flowing. That will pressurize the system, but will not generate enough water to cause a flood. 30 minutes is enough to ensure that you do not have any leaks. However, that does not mean that 20 years from now one, or more, of the fittings will not go bad. ALL plumbing leaks if they survived the initial 30 minutes usually last many years after that, before they start to leak. Usually, but not always, because of something other than a poor installation.