Why would my pressure reducing valve fail after repairing my water main?

Question

I had a main water line bust on my side of the water meter. After fixing it and turning water back on to my house my water heater T&P valve kept releasing spurts of water which found out it was caused by increased water pressure. My PRV was installed two years ago and when i had my plumber come to check out my problem he tested the pressure and found that i had 160 pounds running through my plumbing system after PRV. I have seen problems caused by PRV's going bad and usually it causes a decrease in pressure. What would cause one to fail and cause more pressure? Is this common and what would cause this to happen in PRV that is only two years old?

Answer 1

The most likely cause is that dirt or debris from the water line repair have gotten jammed in the PRV so that it cannot close. You can remove it and see if there's anything visible that can be cleaned, but at that point, you may as well replace it with a new one that you'll know is good.

Answer 2

There is usually a cash valve (pressure reducing valve) somewhere on your supply line. These can fail in a way that they no longer regulate the pressure properly and allow it to become too high. I think the correct answer to your issue sounds like you have a bad cash valve. That would explain the water pressure being too high. Also, it sounds like the PRV is not failed but rather doing it's job of relieving excessive pressure. Common household pressure is 40-45psi, maybe even 50, but not to exceed 60psi.