So as a lot of you know I help my near ninety year old Dad out at his place. I fired up the sprinklers today and in the main vacuum valve there is a rubber o-ring type gasket. It has a split in it. No biggie I can just replace that. Problem is it looks like I am going to have just replace the entire valve from what I can tell. There doesn't seem to be a way to take the valve apart. Am I missing something? Any input would be appreciated.

Here are a couple pictures.


Here you can see the crack.


Everything still works fine but being pressurized it leaks like a siv.

 

That is the back flow preventer valve, also called a vacuum breaker. I’ve tried to repair these in the past to no success. Just replace it! They typically come in 3/4” 1” & 1-1/2” NPT sizes so make sure to get the correct size. You should be able to get one at Home Depot $100.

 

The ones I have seen here in Phoenix are definitely made differently, and are ours are easily repairable. My co-worker has the same one as I do and he was able to take it apart, get a diaphragm from the local irrigation supply store, and rebuild it himself.

 

Looks like the top piece will unscrew so you can access the seal.

Don W

 

Ding Ding Ding. You won. I was just talking to my neighbor. This top appearantly unscrews counter clockwise. I will be over there tomorrow trying. He said I have to buy the top piece with the baffle. I didn't want to break free all these connections.

 

I will take pictures. To help more that need the same help.

 

You can buy a repair kit for those. I think I spent about $15 for the kit at Home Depot. I have replaced a number of those units, entire vacuum brakes. They've gone up in price. I think I spent about $125 for the last one a couple years ago, here in the Denver Metro area.

 

To be honest, the internals of those things usually corrode over time to where replacing the internals is just a short term band aid.

 

If you do replace it, be aware there are several ID sizes. Be sure to replace it with the correct size. Thinking about it, you need to know the correct size in order to get the correct parts kit, as well, LOL

 

The number of different valves they have for these is astonishing. Mine is actually made of plastic, and I'm on my second one. First one detonated one spring on startup, as it had developed a crack due to improper winterization. When I bought my house, the owner and real estate company had not bothered to winterize the system. On the day I took possession, Dec 15, I walked into the house for the first time and could hear water running. The supply pipe had frozen and cracked open outside. So, I shut off the water, drained it as well as I could, and fixed it in the spring. But the valve had developed an unseen crack, thank god no one was near it when I turned the water on. Shrapnel everywhere.

So, this is my evidence to support the next statement: if you have to replace it, replace it with a similar metal valve, and avoid the plastic.

 

I figured out how it comes apart. Many projects so it is back burner for now.
I plan on taking the piece with me to make sure I get the right part.

Thanks for all the input. 👍