Soldering leaking copper cold water supply line in laundry room

[personage]

I would like some advice on repairing the leaking connections in the 90 degree fittings on the bottom pipe. This is cold water supply for the laundry room. There are two small leaks. One where the pipe connects to the 90 degree fitting leading to the shut-off valve, the other is between the short pipe coming out of the 3/4 main supply line and the 90 degree fitting.

I understand that proper repair requires disassembling and resoldering both joints. My question is how to best drain the water, so I can disassemble the connections.

Do I just cut the bottom pipe, so I can drain the water and then replace or patch it with a straight connector?

Any advice on draining the water? The supply line goes two floors up, so I am concerned that there may be a lot of water coming down when I cut the pipe.

Thank you for your help and expert advice.

 

[Terry]

Normally you would shut the water off to the home, and open everything up.
When I say open it all up, that means going upstairs and turning on faucets, and flushing toilets.
If there is an electric water heater, I like to turn the breakers off while I have things shut down. If there is a recirc on the water heater, I unplug that.
Most repairs like that involve cutting the pipe and using new fittings. You have to leave an open end for the heated air to escape from or it will blow a pinhole leak in the last fitting you solder.

 

[Sponsor]

 

[personage]

Thank you, Terry. This is a condo, and the supply line goes two floors up into other units above me. I can shut the water off (the shut off valve is in a common area on the ground floor), but I don't have access to the other units. The good news is that the supply line only serves the laundry rooms. Bathrooms, Kitchens, and heating supply lines are all separate.

I read about stuffing white bread inside the pipe to temporarily block the water, but my guess is that I would still have to drain most of the water before it would be practical.

Would leaving the washing machine faucet open be sufficient for the heated air to escape? Or would you recommend installing a drain coupling on the horizontal pipe, and soldering it last?

 

[Terry]

Anything open is all you need. The washer valve works for that.
If when you cut and no new water is coming up, you can wait until the water from above stops dripping down. It can take a while.

 

[Mliu]

Thank you, Terry. This is a condo, and the supply line goes two floors up into other units above me. I can shut the water off (the shut off valve is in a common area on the ground floor), but I don't have access to the other units. The good news is that the supply line only serves the laundry rooms. Bathrooms, Kitchens, and heating supply lines are all separate.

Presumably, you've informed (or will inform) your upstairs neighbors that you will be shutting off the laundry room water supply. So why not ask one of your top floor neighbors to disconnect the hose connections from their washing machine valves to allow all the water to drain? Once the water is drained out, they can connect their hoses again before you even start your soldering (you don't want them to forget and have them disconnected with the valves open when you turn the water back on again). All you need is to break the suction so the water drains out completely from all the pipes above you. Drain all the floors first through your washing machine supply valves, then you only have what's left in the "U" shaped pipe in your laundry room which you can drain into a bucket when you cut the pipe.

There is nothing worse than opening a pipe and draining the water, starting your soldering repair, and then someone above you opens a valve and dumps trapped water into your pipe (usually happens when you're on your last fitting, so now you have to take things apart again).

Ok, there are worse things, but that's still pretty bad.

 

[Reach4]

You have to leave an open end for the heated air to escape from or it will blow a pinhole leak in the last fitting you solder.

Could that be the source of the personage leak?'

Could the leak be fixed by just applying enough heat to the leaky joint to re-melt the solder after the water has been drained?

 

[Mliu]

Could the leak be fixed by just applying enough heat to the leaky joint to re-melt the solder after the water has been drained?

I wouldn't advise that. Once a pipe has been in service with water leaking, you get both corrosion and mineral deposits in the joint. There's no way to clean that junk out or flux the joint without disassembly. Trying to re-melt the solder in place will leave a contaminated, weak joint (if you're even able to get the solder to seal at all).

 

[Jadnashua]

Could that be the source of the personage leak?'

Could the leak be fixed by just applying enough heat to the leaky joint to re-melt the solder after the water has been drained?

Once water has moved through a fitting, it will leave some corrosion and/or moisture behind and you will not get a reliable connection without taking it apart, cleaning things, and refluxing, then soldering. Now, if you tested with air, and it leaked, you could possibly reheat and add solder, but that may not work, either. A common issue when it leaks is:
- not heating all around or heating the pipe and not the fitting
- not cleaning well
- not fluxing or gaps
- overheating the joint and burning out all of the flux.
- not applying enough solder

Unless the water was perfectly pure, almost impossible, once water flows through, it won't flow solder properly to make a proper seal.

 

[Terry]

If you have a leaking copper joint, the only repair you can do is to start over.
Everything gets removed and either cleaned up or tossed.
New flux and new solder. Anything less and you will be there all day until you give in and do it right.

 

[MACPLUMB]

Or you just use a couple of SHARKBITE fittings, then you don't have to worry about the water

 

[Reach4]

If 3/4, maybe one SharkBite U256LF

Maybe not. You would have to get the cuts just right, and there may not be enough pipe without the solder on it.

 

[personage]

Thank you, everyone. Great advice!

All fixed. Ended up cutting the existing pipe to drain and replacing it with a new one. Was surprised how little water came out, only about about a gallon. Put paper towels underneath the seams and let the water run for a few minutes-- pipe is cold but all dry.