How do you know when a gas valve is open and when it is closed?

The natural gas shut off valve in the picture below is installed behind my oven. Usually when I see a valve like this, if I turn it 90 degrees, it will turn until it stops. When it stops 90 degrees from where it started, the valve is off.

However, with this valve, it doesn't stop at 90 degrees. It continues turning 180 degrees until it's facing the other direction. The valve is on in both of those positions. If I stop turning the valve at 90 degrees, it does appear to shut off, but like I said, nothing stop me from continuing to turn the valve to 180 degrees.

Is the valve meant to function this way or was something installed incorrectly? It seems strange to me to not have the valve stop at 90 degrees so you know it is definitely off. The way it is now you are basically guessing that you have properly turned the valve 90 degrees to shut the gas off.

Is this right?

Although you may never need to shut off the natural gas supply to your home, you might need to if you’re renovating, boarding up the house, or preparing for a natural disaster. In these circumstances, valves can be turned off to prevent a gas leak from happening or to stop gas from getting into the home.

If there’s ever a strong gas smell in the home, don’t try to shut off the gas yourself. Leave the home immediately and call your utility company from a safe location. Keep reading to learn where to find your gas shut-off valve and how to turn it off.

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How to locate your main gas shut-off valve

Gas shut-off valves can be located in different places in the home, seldom in a place you regularly see. Here are a few places you might find your gas shut-off valve:

1. Outside your home—These valves, also called street-side valves, are located by gas meters on the side or front of the house. They’re often rectangular in shape and may be enclosed in a cabinet. Although you could turn off the main valve by using a wrench, your gas company will likely want you to shut off the portion of the valve that’s located inside your house.
2. Inside your home—There will likely be a ball valve, sometimes called a house side valve, located within your home. You may find this valve near the location where the natural gas pipe enters your home. Even if the valve isn’t right near the entry point of the home, it should be located before the pipe reaches the first gas appliance.

Note that the age of your home plays a role in the valve’s location. In older homes, there may not be a valve inside the home at all. In newer houses, it’s often true that these valves are located close to the home’s water heater or furnace.

How to turn off the gas shut-off valve

If you’re in a non-emergency situation where you need to shut off the gas valve, you can shut it off yourself. It bears repeating, though, that if there is any chance of a significant gas leak, leave the home and call your local gas company or fire department.

Materials

Wrench (crescent or 12-inch adjustable)

Gas shut-off wrench (you can use a more general wrench but may want to buy one of these)

Once you’ve located your gas shut-off valve, here’s how to turn it off:

1. Take your wrench and turn the valve 90 degrees in either direction. The valve should now be crossways to the main incoming gas line.
2. Check to see that the gas pipe-valve combo looks like a plus sign to verify that it’s shut off.
3. If you’re wondering whether the gas shut-off valve is on or off, remember that when the pipe is running parallel to the line, it’s on; when the pipe is perpendicular to the valve, it’s off.

How to turn on your gas shut-off valve

It’s generally recommended that, rather than turning the gas back on yourself, you contact the natural gas company or fire department so they can do a safety inspection before turning the gas service back on.

Additional safety considerations

As a proactive strategy, install carbon monoxide detectors where gas leaks could potentially occur. Have natural gas appliances, your vents, and any ductwork checked by an expert every year—this will help prevent carbon monoxide poisoning for people and pets in your home.

How to turn off the gas shut-off valve to appliances

Gas shut-off valve code requirements now mandate that these valves are in the same room as the appliance, with the valve being within six feet of said appliance. If you find that one of your appliances doesn’t meet these code requirements, contact your gas company to find out how this should be remedied.

Gas stove or oven

1. If you need to ventilate the area, open the windows. Don’t turn on an electric fan or light until the gas valve is shut off.
2. Verify that all stove burners are completely in the “off” position.
3. Pull out the oven drawer and empty it, then remove the drawer.
4. Use a battery-powered flashlight to see if you can spot the gas shut-off valve.
5. Once you locate it, use your wrench to turn the handle one quarter of the way, making a plus sign with the gas pipe.
6. Once the valve is off, turn on one burner to test the gas supply.

If you can’t access the valve from the drawer, see if you can locate it by reaching behind the stove. If that doesn’t work, you’ll probably need to gently move the stove without putting stress on the flexible tubing or disconnecting the plug from the electrical outlet. If there’s no gas shut-off valve behind the stove, it may be in a crawl space in the floor or in a nearby cabinet.

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Gas furnace or boiler

1. With a furnace, the furnace gas valve is often located near the bottom of the appliance; if your gas furnace has a pilot light, its gas shut-off valve should be close to that device.
2. If you don’t see your valve, your furnace owner’s manual can help provide guidance.
3. Once you locate the gas shut-off valve, turn the valve so that it’s at a 90-degree angle to the pipe (a quarter turn).

Gas water heater

1. Locate a single handle, usually at the bottom of the water heater.
2. Turn the valve clockwise to shut off gas to the appliance.

Gas-fueled fireplace

1. Gas fireplaces typically come with a control panel, often hidden behind the front screen. Gently tug on the screen to get access to the panel.
2. Locate the knob that controls the flow of gas. It may have the options for on, off, and pilot.
3. To turn off the gas, simply put the knob on the “off” position.
4. If you need to cut off gas service entirely to the fireplace, locate the shut-off valve going to the gas line, and turn it 90 degrees. 

If you can’t find the gas shut-off valve for a specific appliance, you may need to shut off the main gas valve to address the problem.