Water ball valve for sprinklers leaks when turning on--by design?

[rschissler]

Having moved to a house in a new area, I tried turning on the water to the irrigation sprinklers.  It was off for winter. It's a ball valve embedded in dirt near the street and main water shutoff box.  When I started turning the handle, water started shooting out from it.  This freaked me out, so I shut it back off.  

I talked to a friend and he said it was normal.  I found this hard to believe as I had never heard of that before with a ball valve.  He also said that you should turn off the water at the box first, so that the valve area doesn't fill up with water and mud.

Is this right or wrong?

[blackhat]

Was the water coming out the side of the valve or around the handle?  There is a design of valve that is self draining. Basically, a small bled port in the side of the valve is opened during off and approximately the first 30ish degrees of rotation towards on. This allows the line to drain when the valve is closed. A sprinkler line might be an appropriate use for that style of valve.

[rschissler]

Was the water coming out the side of the valve or around the handle?  There is a design of valve that is self draining. Basically, a small bled port in the side of the valve is opened during off and approximately the first 30ish degrees of rotation towards on. This allows the line to drain when the valve is closed. A sprinkler line might be an appropriate use for that style of valve.

I couldn't see it directly, because the hole was too deep, but it was on the side, kind of underneath.  That does make sense, so any water left at the valve drains out, so as not to freeze.

[TDKPE]

Self-draining ball valves are designed to drain the downstream piping when closed.  The drain should not vent anything when the ball valve is open.

It's possible the ball is 180 deg. out of phase.  That may happen if someone takes the handle off and puts it back on aimed the wrong way.  Is the valve even installed with the flow direction correct?

By the way, the dry barrel fire hydrants you see on the street in the north are made the same way, only bigger.  The valve is on the water main, and is self-draining when closed.  The nut on top of the hydrant is attached to a long rod that goes down inside the hydrant to the valve on the water main, and there's a big drain hole where the tee goes vertical to the hydrant.  They don't leak when the hydrant is active, but they drain down when the valve is shut.  If they didn't, they'd explode in cold weather.  But they don't shoot a stream of water in the air when someone runs one over with a car like on TV, probably because all those scenes are shot in southern California where 'wet barrel' fire hydrants are common.  


Re-reading blackhat's comments, it could be as he suggested that you didn't turn the handle far enough to close that bleed hole. I gotta read more carefully before expounding.

[MarkSingleton]

 shoot a stream of water in the air when someone runs one over with a car like on TV, probably because all those scenes are shot in southern California where 'wet barrel' fire hydrants are common.


   Having seen more than my share of sheared fire hydrants, I can attest that the TV/movie scenes are 
accurate.


   Upon seeing "Old Faithful" at Yellowstone Park, I was, shall we say, underwhelmed.