I tried blowing out my sprinkler system and the pressure blew right though the top. I unscrewed the top dome and found that the metal seal with a rubber seal had worn away, there was a thin piece of rubber on the seal. Unfortunately, there is metal piece across the middle of the opening, which has a downward facing spring and a metal rod in the center to hold the valve in place. I tried cutting a tennis ball in half, but, I had to cut the tennis ball to fit around the metal rod. It did not work and my alternative is to disassemble the unit. Any suggestions?

  • This is going to need a picture. There are many valve designs, and we can't tell what you have.
    – JPhi1618
    Oct 29 '19 at 17:49
  • 1
    It's an Apollo Model #4050500 with a serial #CD924.
    – Tim D
    Oct 29 '19 at 21:01

That sounds like the vacuum breaker valve that prevents back-flow. They are generally required by law in sprinkler systems. In 1996 our county started requiring spring loaded types. There are many designs . If you can't find a replacement part from the manufacturer , you may need to replace the valve. If you replace the valve , the city or county may want to inspect it.

  • 1
    Most manufacturers have rebuild kits for them.
    – JRaef
    Oct 29 '19 at 19:38

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