Is this a backflow problem?

[nmbexcuse]

I need to relocate my water heater to another location. So on Saturday I disconnected my water heater.

I first turned off the power to it, then I disconnected the wiring. Then I flipped the "hissing" valve on top, connected a garden hose to the bottom drain and let it drained out.

Next I needed to turn the water supply off. There was a gate valve right there and I turned - it broke off - all corroded and the stem just broke. So I went and shut off the main water valve, then disconnected the water supply.

Next is the hot water feed that comes out of the heater. I removed that too, and some water came out, as expected.

After the water heater was drained I moved it out of the way.

Next I cut off the water supply and capped it with a 3/4" sharkbite end stop. I then turned the main water back on. Everything should be ok right?

No...now water came out of the hot water line that was connected to the heater. That line is supposed to be fed by the water heater and now is not even under pressure, so where is the water coming from? This water is not under pressure but it's slowly pouring out of the line.

I understand the hot water and cold water lines are supposed to be disconnected, the only connection is through the hot water heater which is now disconnected. So why do I have water coming out? Unless there is another "cross over" from the cold water line? The fact that this hot water line is no longer under pressure, is causing water from somewhere else to be drawn in?

I don't think this is normal, or is it? HELP...Thanks in advance.

[charlie]

an internally leaking faucet somewhere.

[nmbexcuse]

Really?

Well I am in the process of gutting the house, and have already removed all faucets, toilets, etc...everything is shut off. Except for one outdoor faucet in the bar area and six hose bibs but those are turned off too.

So it has to be that faucet right? How can I diagnose that?

Thanks!

[DerbyDad03]

Here's a guess:

You have a single handle anti-scald shower valve in you house . Since these devices are spring-loaded to continually balance the pressure beween hot and cold, the lack of pressure on the hot side is forcing water past the valve and into the hot side.

BTW, speaking of back pressure problems -

I Installed a hot water hose bib at the front of my house. It is connected to the cold bib by a Y-hose. The cold water feed is before the house's pressure reduction valve (i.e. full street pressure), while the hot feed obviously is not. If I leave the bibs open with a closed hose attached, the cold water feed will force it's way back through the Y-hose and into the house plumbing. It's get's really wierd since it essentially reverses the flow of water in my house - the cold faucets and toilets produce warm water and the hot faucets produce cold. It really spooked us the first time it happened and it took me a while to figure out what was going on.

[Speedy Jim]

Yes. Cross-connect between Hot and Cold.

That would rule out any cold-only hose bibs.

That leaves Single lever shower controls, Single lever faucets, AND Washing machine solenoid inlet valve.

There could be other special types, but those are the common ones.

Jim

[Eric]

As other posters have indicated, any faucet or appliance that's connected both to hot and cold (that generally rules out outdoor connetions) could be the culprit.

Or... there's something called a "tempering valve" that mixes hot + cold water to reduce the temperature. Often used to extend the hot water supply by allowing the heater to be set higher, then adding cold to make the desired temperature. They're usually located near the water heater, but could also be near a fixture.

Eric Law