RI Lawn Sprinklers Ohio Irrigation Blog

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Thursday, July 30, 2009

Cracked Irrigation Valve

Irrigation Valves that develop a crack and fail:

OK- a side note since one valve had a bad production run and I want to bring this to your attention so that it is not confused with valves that fail due to improper installation techniques: Rain Bird had production issues with their Jar Top valve in the past and have since corrected the problem. If you have a Rain Bird Jar Top valve(s) that have failed along a seam then you should consult your local Rain Bird supplier for any options you may have.

Valves that develop cracks other then the Rain Bird Jar Top.

The short answer is they most likely the valves were over tightened when they are installed if they are the female thread style. Each female thread valve is connected to a male thread on the manifold tee. By design the male threaded fittings are slightly narrower at the end of the fitting and gradually widen towards the base of the fitting. When someone is assembling a female valve onto a male threaded fitting they should follow the following rule: hand tighten the valve and then turn one additional rotation with the proper tool and as always only use the proper amount of Teflon tape (no dope.)
If someone wrenches the valve one and applies too much pressure they have pushed the female threads into the wider area of the male threads causing an increase of pressure on the valve that will some day fail under the increase of pressure. If you have this problem and you have to replace a valve you should consider replacing the remaining valves if they have to be excavated since the chances are good that the other valves were installed in the same manner.

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