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View Full Version : Plumbing water tank relation to cold water pressure?


CURaiderDude
Jun 4, 2011, 07:38 AM
I have shut off the main water feed at the road, shut off the main disconnect in the house to do an outside faucet line repair. I've got all the new pieces sweated into place, except for one. Back flow water continues to drip out of this one connection, preventing me from making my last solder. I can't make this water completely shut off, though I've opened and closed every cold water line in the house. One odd thing... if I open the pressure relief valve on my hot water tank most of the cold water faucets in the house begin to run rather consistently. Weird huh?

massplumber2008
Jun 4, 2011, 10:49 AM
Hi Crd...

You said, " opened and then closed" every water line. Here is probably where your issue is... ;)

OPEN all faucets and leave them all open until it is time to fill/test the system.

If the issue continues, shut the cold water shutoff into the water heater (so hot water can't be pulled back into the cold water) and then, only if needed, disconnect the water meter and drop it out for a few minutes while you make the final solder joint... should work!

Worst case, go get a couple sharkbite or gatorbite PUSH FIT type fittings and connect your piping using these fittings that do not require any soldering (available at all home improvement stores).

Let us know how you make out, OK?

Mark

PS: Be sure to keep the new outside faucet open while soldering, too!!

CURaiderDude
Jun 5, 2011, 06:57 AM
You were right on Mark. It was hot water backing up into cold water intake line. Once I finally got the final leaking to stop the solder still wouldn't work, so (like you said) a compression fitting was the solution. All works great now! Thanks for your help! Rob

CURaiderDude
Jun 5, 2011, 07:05 AM
Hot water was backing up into the cold water intake line. I shut off the hot water tank cold water intake valve, after draining about 15 gallons of hot water from the tank (to help relieve the pressure). I still couldn't get the solder to work on the last, tricky connection, so a compression fitting did the trick (no solder required). So a compression fitting was the solution.

KenSayers
Jun 6, 2011, 06:30 AM
For future use, to stop slight drips from fouling up your sweating of fittings, I will cram a bit of white bread into the line. That stops the water long enough to solder and then dissolves in the water. Note, do not use the crust.

CURaiderDude
Jun 6, 2011, 06:48 AM
Ah, yes... good advice.

massplumber2008
Jun 6, 2011, 07:32 AM
I guess if homeowner wanted to try the bread they could, but it really shouldn't be necessary.

If you open all faucets and drain the water from the system, and shut the cold water feed into the water heater then you should be all set.

I have trained probably 50-60 commercial/residential apprentices/plumbers over the years and whenever they had issues with soldering I could always come along and resolve it by simply draining everything, isolating boilers/water heaters or, worst case, dropping the water meter itself.

Thanks for posting guys!

Mark