What is it called and what does it do?
Is there a way to know if gas is available?
This bottom of the pipe leads to a stove.

Photo >

  • One part of the question is how would you know if gas is available. This is a shut-off valve and it is presumptively turned off. What appliance is this connected to? First guess is the lower tube is the outlet. What does the lower tube lead to? Jul 10, 2023 at 20:45
  • To determine if gas is available a competent gas plumber would make a presumptive determination of which way the gas was flowing, then disconnect the presumed outlet fitting at the valve, in this case disconnect the lower hose, cautiously. No gas should flow because the valve is closed. (If gas does flow continuously, then presumably the wrong choice of direction of flow was made.) The plumber would then cautiously open the valve. If gas is available, there would be a hissing sound and smell of natural gas (mercaptan odorant). Be prepared to shut the valve quickly. Jul 10, 2023 at 20:57
  • Do you have access to the gas meter? Is the valve at the meter open? If not, you would have to get the gas supplier to turn on the valve at the meter. Jul 10, 2023 at 21:03
  • Another way to proceed would be to identify the appliance that the outlet side of this valve goes to. Presumably this will lead to a gas cooking stove or a gas fired water heater or a furnace. Maybe the appliance has been disconnected and even removed. Which is it in your case? If it is a cooking stove, you could try to get the stove operating.Tell us what you have so we don't have to give instructions for every possibility. Jul 11, 2023 at 16:26

2 Answers 2


These valves are simple in operation>

If the handle is inline with the pipe then it is open,

If the handle is "across" the pipe then the valve is closed.

The valve itself is a ball with a hole through it.

  • 1
    @JimStewart CW in North America and Europe. CCW in Australia and South America :-) Jul 10, 2023 at 14:27
  • 1
    @manassehkatz I think you mean ACW, not CCW :-) Jul 10, 2023 at 14:37
  • 1
    @JimStewart the picture shows a stop tab at top of valve ... it can only turn CCW
    – jsotola
    Jul 10, 2023 at 15:52
  • @jstola I think you are correct. Also there is a double arrow on the handle which indicates that "O" is CCW and "S" is CW. Jul 10, 2023 at 16:36
  • 1
    Speaking from experience: Those valves exist also in a "childproof" variant. One needs to push the handle to unlock it.
    – Martin
    Jul 12, 2023 at 9:13

One part of the question is how would you know if gas is available. This is a shut-off valve and it appears to be off or shut. I believe on the handle the "O" is for open and the "S" is for shut.

What appliance is this connected to? First guess is the lower tube is the outlet. Where does that line lead? Is it connected to anything?

You should not open the valve until you verify that there are no open lines downstream of this valve. Alternatively, you can disconnect the outlet fitting at the valve.

The safest way to proceed would be to gradually loosen the fitting on the outlet line which we have identified as probably the lower line. Loosen it in stages and listen for hissing and the odor of gas. This is with the valve shut as it is now.

If you get no continuous hissing and odor of gas, then loosen the fitting completely and gently separate the lower line from the valve. Now slowly open the valve and listen for hissing and odor of gas. If gas flows, let it flow for a few seconds to establish that there is a continuous flow of gas, then shut the valve. You will have the answer. You have gas.

Now reconnect the lower line and snug it tight but do not overtighten.

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