Backflow valve question

[stinkbelly]

Why does this backflow valve have a valve stem on it? This is on my water well. That is the pressure switch attached to it. My other backflow valve looks the same without the valve stem.



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[Skinny]

So you can take a pressure reading?


Skinny

[Youngblood]

So the Plumbing Inspector can check it for proper operation.

You can get the water pressure reading from it if you wanted too.


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[Paycheck]

They use air to determine the water level in the well.

[Nike]

Sniffer valve

Draws air in when the well shuts down.

[double bogey]

That looks like it is there to bleed air manually. Looks like an ordinary Schrader valve. But I'm not a well guy, so could be just a pressure tap.

[jstanton]

Sniffer valve

Draws air in when the well shuts down.

This ^^^^^

It's called a Snifter Valve, but is essentially a Schrader valve.

Inside the well inline with the pump column pipe 21' down there will be a bleeder orifice. When the pump turns off the bleeder orifice will drain the water from the first 21' of column pipe. As it drains it creates a vacuum and opens the snifter valve to draw air into the column pipe. The next time the pump turns on the water pushes the air into your galvanized pressure tank and recharges the air. In the side of your pressure tank you will have an air volume control valve that regulates the proper ratio of air to water.

If you ever notice the well rapid cycling on/off check to make sure your tank is not water logged. If it is this is most likely from a failed air volume control valve or a bad Schrader valve.

Feel free to PM me if you have any more water well or pump system questions!

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[stinkbelly]

Now I am confused.

I have this snifter valve next to my pressure tank. About 40 feet away is the well head. I have an additional backflow valve at the well head. How can the water drain back down the pipe with the backflow valve between the snifter valve and the well?