hot and cold water mixing somewhere

[Nelson]

Hello,

I'm doing some plumbing for a friend and ran into the following problem. After testing all of the roughed in water pipes and valves, it was time to hook up some fixtures. I turned off the hot and cold stop & waste valves in the basement and, starting with the cold side, loosened the little valve on the side to drain the water. It seemed like it was taking an awfully long time to drain and then I noticed that the water coming out was hot!

So, I have an unwanted loop somewhere, and I'm wondering how to go about finding it. I assume it's through a valve, and my prime suspect is the washing machine valve. But there are other possibilites -- shower? sink?

Any suggestions on the best way to troubleshoot this problem?

Thanks very much,

Nelson

[Mike Grooms]

Nelson,

I assume the problem wasn't there before the rough-in, right? If that's true, then the pipes you installed are somehow crossed. To eliminate your hope that it's the washing machine, shut the hoses off and recheck.

I think you either ran a hot water line to a cold outlet, or you somehow looped them together.

Of course, it could be something freaky, like a recirculating line, but these aren't usually put in home installations. If you do a little more detective work, please write back with the info.

[Ned Flanders]

turn off every valve in house shut off the cold inlet valve to your hot water maker turn on the main cold feed. go turn on each valve one at a time and see if one of the hots comes on. I pipe my hot water supply as the first tee in my cold main, I can shut a valve and have only the hot turned on. I dont know how you have piped your system or valved it and if it is possible to have the hot on without the cold being on. But you should be able to check with the cold only on.