I just rebuilt my Zurn Wilkins 600XL 1" pressure regulator, but it still is not controlling the pressure after rebuild.
One thing I notice is if I measure the pressure immediately after closing a running faucet, I'll see the pressure slowly rising till it gets to abt 110psi (which I assume is city pressure levels).
I pulled it apart again after re-installing, and I noticed two large chips in the bore where the stem unit sits. The chips straddle where the O-ring sits in the bore (those black lines in the center of the bore is residue from where the O-ring sits).
The regulator core sits facing a wall, so I couldn't see the chips the first time I re-assembled. I could only feel the roughness manually w/my finger, but I ignored it. It wasn't till after the unit was re-installed and still not regulating that I started wracking my brain to think what it could be. The roughness I had felt was the only thing I could think of, so I decided to go back in and actually turn the valve unit so I could see into the bore, and that's when I noticed those big chips.
This YouTube video says that bore needs to be smooth to for the regulator to function properly: How to Repair a Water Pressure Regulator | Zurn Wilkins 600XL (https://youtu.be/eI334pzRWDQ)
My theory is that those chips in the bore are allowing water to bypass the O-ring, and so not adjusting the water pressure; a little bit of water slowly seeps through those chips raising the pressure in the house system till it reaches parity with the city pressure.
This theory is inline with the behavior I saw where the pressure slowly increases when measuring immediately after closing a running faucet.
I can't explain how those two large chips got there in the bore, though.
I'll go to hardware store today and buy a whole new unit, and see if replacing the whole thing fixes the issue.
My questions are:
- Are those chips causing the regulator to not regulate the water pressure?
- What could have caused those chips? How could they have got in there?