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Post by Auf Kiltre on Dec 18, 2022 15:25:42 GMT -5
Preparing for temps in the upper teens later this week I shut off our lawn irrigation system. In doing so got a full spray from a discovered crack on the bottom side of the brass fitting post pressure vacuum breaker. I had that part replaced after it cracked 2 years ago and suspect this part was also cracked, but only reveals itself when closed with the incoming valve to the vacuum breaker still open. With both closed no leak. I assume the cracked brass piece has no pressure on it when opened because of internal structure/design bypassing water flow to the cracked area?? 2nd pic is the crack on the bottom of the fitting.   |
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Post by RufusTeleStrat on Dec 18, 2022 17:17:07 GMT -5
Since it is a ball valve, my guess is the internals bypass that area when open regardless of other valve positions, but when closed diverts the water pressure to that side where the crack appears to provide the leak.
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Post by Auf Kiltre on Dec 18, 2022 17:59:28 GMT -5
Yeah, that's my guess too. Now to find a suitable replacement. I don't want to buy a cheap Amazon/Big Box piece of junk since this thing will endure the Texas brutality of temp extremes.
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Post by munkiejunque on Dec 19, 2022 11:53:56 GMT -5
No affiliation, but I have had good luck with these guys. As always YMMV.
Supplyhouse.com
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Post by Jim D. on Dec 19, 2022 12:21:12 GMT -5
When a ball valve is fully open, the valve body is not under pressure. When closed, the area between the actuating ball and the body is under full pressure. The cracked body of yours will also leak when partially closed but not to the degree of fully closed. Yours was damaged by water freezing and expanding when there was remaining water in the valve body. In prepping an irrigation system for winter that valve should be blown out with air after the system is closed off and left partially open-about half way.
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Post by Auf Kiltre on Dec 19, 2022 12:37:21 GMT -5
When a ball valve is fully open, the valve body is not under pressure. When closed, the area between the actuating ball and the body is under full pressure. The cracked body of yours will also leak when partially closed but not to the degree of fully closed. Yours was damaged by water freezing and expanding when there was remaining water in the valve body. In prepping an irrigation system for winter that valve should be blown out with air after the system is closed off and left partially open-about half way. The only place I can imagine blowing out with air is via the 2 bleeder valves on the connected vacuum breaker. I had shut this whole ensemble down and opened those valves during the dastardly Feb 2021 ice storm and still had to replace vacuum breaker because it cracked. I'm certain this valve was damaged then too and only discovered when I shut it off before the inlet. Thanks for the info guys. Think I'll run out to Ace since it's the place with the helpful hardware man as opposed to Lowe's. |
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Post by Jim D. on Dec 19, 2022 12:56:07 GMT -5
The bleeder valves are where you blow out the system with air. Those need to remain half open when finished. It takes a high air volume to completely blow out the system including the heads as you cycle through the zones. I have mine done by a pro in the fall.
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Post by Peegoo 🏁 on Dec 20, 2022 15:06:18 GMT -5
It's leaking in the closed position because of how the quarter turn valve ball is constructed: there's a large hole (tunnel) through the center of the ball. In the open position, the tunnel through the ball is parallel to the pipes connected to the valve. When closed, the tunnel rotates to a 90-degree orientation in relation to the pipes. The seal on the ball relies on a tight fit on the ball all then way around the valve body (yellow outline). Because the crack in the casting extends beyond this area, (red circle), it's probably leaking from that point.  |
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Post by Auf Kiltre on Dec 20, 2022 15:56:37 GMT -5
It's leaking in the closed position because of how the quarter turn valve ball is constructed: Yep, once I looked inside a ball valve and saw how it's constructed it made sense. Bought a replacement today, quite the upcoming apocalypse line of people cradling faucet covers and pipe wrap. I closed off my irrigation system and drained the best I could, but no blow out because I don't have a compressor. Then I wrapped the sumb itchy with insulation, duct taped that, then covered with a construction grade garbage bag, then taped that! I hope she holds through 3 days of sub freezing temps. |
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