Backflow preventer relief valve won't seal after rebuild

[DJbentle]

I have a Febco 825Y rpz backflow preventer that I inherited with a house I recently moved into. It had a small drip leak from the relief valve. I disassembled it and found the plastic on the relief valve assembly was broken. I replaced the relief valve assembly completely, and changed the seals on both check valves.

After reassembling water gushes from the relief valve when I turn on the feed. It doesn't matter whether there is flow or no flow, although I don't think I get any water through it even with the output open and a spigot open downstream. If I open test cock 3 the relief valve will close and water flows from the test cock. As soon as I close the test cock, the relief valve opens again.

Anyway, I know I need to get it inspected, but I want to make sure it's working first. I'd greatly appreciate any other troubleshooting steps I can try to track down the issue. All the seats and seals look good and I didn't see any debris anywhere.

 

[James Henry]

Close the house side and open the street side very slowly.

 

[Sponsor]

 

[James Henry]

By the way you have to be certified to work on it anyway. Just call a plumber that is certified to fix and test it.

 

[DJbentle]

Close the house side and open the street side very slowly.

Thanks a lot for the help. I tried that and I still couldn't get it, but I managed to figure out what the problem was. For the next guy that is as stupid as me, I some how mixed up the springs on check valve one and two. I didn't even realize they weren't the same spring weight. I swapped them back and pressurizing slowly like you said worked great.

 

[DJbentle]

By the way you have to be certified to work on it anyway. Just call a plumber that is certified to fix and test it.

I will get it tested, I'm not sure when the last time it was tested was, since I'm new at the property. I was just hoping it would be cheaper to just test than to rebuild and test.

 

[Jeff H Young]

I've got an 825y as well I never worked on one but worked through it. This is on my irrigation at my house. None of my other homes had one all the sprinkler valves are anti siphon. So I'm pretty confident I'm not going to cross contaminate. My city doesn't require testing, although It might require it tested by a certified backflow tech if worked on. But no annual test. So no plan to have it tested by a tech