turning off supply correctly

[Cal Dershowitz]

I'm turning off supply in a house that is new to me. I think that I'm able to shut off the supply as it comes into the house. I opened some faucets and let it drain and flushed a toilet, but it never came to null in terms of flux.

These faucets sit gravitionally-equal to the center of the hot water heater, so I figure I have to turn off the supply to the hot water heater as well in order to stop that from wanting to leave the heater.

Have I diagnosed my problem correctly, and can I leave the pilot light on for all this safely? I could have the supply off for as much as a day.

[DerbyDad03]

Have you opened the highest and lowest faucets as well as faucets In between? With the top most and lowest faucets open, all water should drain from the system.

If the flow doesn't eventually stop, I would check the meter. If it is registering flow with the faucets open and the main shutoff closed, then the main isn't really closed. It could be bad. If that's the case, you'll need to call your local water authority and have them shut the water off at the street so you can fix your shutoff.

One more tip related to shutoffs: whenever you open a shutoff, you should open it all the way and then close it about 1/8 of a turn. If you leave it open all the way, you have no "play" should it get stuck due to corrosion, etc. If it's left fully open, you might not be able to close it, which could be an issue in an emergency.

[Stormin Mormon]

Which supply? supply Air, gas, propane, fuel oil? Cat food?

[Don Y]

First, it is entirely possible that the "shutoff" doesn't shut, completely. Many of these (esp older) were gate valves which are notorious for not shutting off after years of unuse (it's literally a "gate" that slides down to block the water path through the valve -- calcifications, etc. end up preventing it from seating completely after longs periods of unuse)

Second, your hot water supply is probably back feeding into the cold water supply (in the absence of any positive pressure) so there will be some flow until it, too, is depleted (assuming the shutoff *does* function properly).

Look for outdoor hose bibbs as well.

Turn off the water heater if you expect it to drain. You don't want to be heating an empty vessel!

Resist the temptation to drain the water heater from the "boiler drain" that is present in the side of the water heater. Again, these things are so rarely used that you might find *opening* it leaves you with a valve that you can never *close* properly, afterwards! (why make extra work for yourself, *now*?)

What's the reason you are turning the water supply off?

[John G]

In some juristictions a Non Return valve is required to stop the hot water feeding back into the cold (and Town) system.

[gfretwell]

If you open the faucets above and below the water heater air will enter the pipes and break the siphon that would be necessary to drain the heater. You should still run the hot water until all the air is out (after restoring water pressure) before you turn the heat on, just to be sure it is full.

[Don Y]

Here, you just install a heat trap (primarily for your own efficiency). Pressure reducing valve (drops the 100+ PSI municipal supply down to something more manageable for appliances -- which, I think, expect ~80PSI max) effectively prevents water from reentering the municipal supply.

Here, we worry more about irrigation water being siphoned back into the municipal supply (e.g., if a fire engine pulls a vacuum on a local hydrant or supply pressure fails for other reasons). People like to use *lots* of herbicides and insecticides in their "lawns", here.

[gfretwell]

All water lines are required to have backflow preventers here. There are usually 2 check valves in that assembly.

[Don Y]

"Requirements" seem to have little to do with what is *actually* installed, here.

E.g., irrigation supply is supposed to have an anti-siphon device installed 12" (or more) above the highest point in the system. I can walk around the neighborhood and count the number of homes that have these installed -- on a single *hand*!

Few homes have pressure regulators (not a requirement, just something you do if you value your plumbing and appliances!) and most folks aren't aware that the city has been increasing supply pressure to accommodate increased demand without increasing the sizes of the lines that supply the water to homes. And, few folks have considered the extra head required to lift the water the 30-40 ft from the local well up to the level of the street that "feeds" our subdivision.

Homes *with* pressure regulators seldom have expansion tanks installed. As a result, the pressure regulator does little to "protect" the plumbing when there is a fair bit of hot water demand.

Rainwater collection tanks are supposed to be located 10 ft from property lines. Yet, most are located in side yards and easily violate that constraint.

Etc.

With the exception of expansion tanks, virtually all of this stuff is visible to anyone driving down the street...

[jaspar203]

Why???? This makes no sense.....

[Cal Dershowitz]

Thx all for comments. I know it sounds banal as heck, and youtubing was a good resource, but I always find that I believe what I'm doing is correct when I hear it in a peer-moderated forum.

I turned off the main (water) supply, then closed the supply to the water heater...faucets open above and below...sawzall out shower faucet...make new stubs with galvanized half inch pipe with caps, ready for transition to copper.

Is there anything about the transition from a male galvanized nipple to a female copper adapter that is trickier than use thread seal and tension properly?

I never drained it, never turned it off, but I appreciate the tip to bleed out any air.

It made me go do it, and I heard a bump indicating something was still not completely water.

[Harry K]

I've never seen a water heater that didn't have its own drain valve.

Harry K