I realized that if a shrubbery nozzle gets accidentally cut off by a hedge trimmer and goes undetected, when the sprinklers run the resulting geyser would hit the eave of my house, causing a lot of water damage. I looked for some kind of valve that would cut off the water to a sprinkler should the flow get to a point that would indicate a broken sprinkler. I found two similar products, Geyser STOP and Geyser Miser. Geyser STOP is the smaller of the two and wouldn't be that visible on shrubbery nozzles. Geyser STOP can only be installed vertically. Geyser Miser is bigger, but can be installed in any plane. It would be good for a side-fed sprayhead.
But, do these products actually work as advertised? Has anyone tried either one of these?
Since I had not received any responses, I went ahead and ordered a Geyser STOP and tested it. I installed it on a shrubbery riser about 3 inches above ground, with another 18 inches of riser above it. It does immediately cut off the water flow if you simulate a cut riser by removing the spray nozzle. However, during normal operation the water flowing pass the steel ball in the Geyser STOP causes a vibration that makes the whole riser shake quite a lot. I have asked Geyser STOP support to comment on this. I expect that vibration wouldn't be a problem for installations on an underground riser feeding an in-ground sprayhead or rotor.
I requested and received a Geyser Miser from the company for evaluation. I tested it in the same configuration as the Geyser STOP, i. e. in a shrubbery riser with an extension above it. Unlike the Geyser STOP which can be installed either direction, the Geyser Miser is unidirectional. It is easy to install it the wrong way and it will simply shut off the water. So easy, that I did it. Once I turned it around it worked perfectly with no vibration at all. It is about twice the diameter as the Geyser STOP and is green. I prefer black to match shrubbery riser piping.
As to the support email I sent to Geyser STOP, it has almost been two weeks and no reply.
Of the two products:
Only works within 15 degrees of vertical
Causes shrubbery riser to shake a lot
Company did not respond to support email
Works in any position
Does not vibrate
Responsive company that provides free evaluation kit