Rise in water pressure.

[Betadine]

I recently had a plumber reroute our pipes because of a slab leak. After the job was done we noticed that our water pressure was 100psi. The plumber said we need to change the pressure regulator valve. We have a Watts N35B which is obsolete. The pressure for this valve is 25 to 75psi. The plumber said that the high pressure was the reason for the slab leak. He offered to change it for $400. A second plumber told me that the pressure was not an issue. Copper pipes should handle pressures up to 200psi. He said the leak was caused by something in he ground like a rock against the pipe. Who's right?

 

[waterwelldude]

Your pressure regulator should be changed. With pressures over 70psi some fixtures can start to leak.
The 2nd plumber, I wouldn't let him back in my house.
I don't know if that 400 is a good or bad price, we don't do much work on those.
I do know that that kind of pressure can cause leaks and broken pipes, and can make a huge mess in the house when a pipe or fitting leaks or breaks.

 

[Betadine]

Thanks for the feedback, waterwelldude. Would changing the PRV myself be an easy thing? Remember, the part is obsolete. Do I have to go with the same brand (Watts N35B)? Or is there a similar replacement? Wilkins? How about repair kits?

 

[Mr_David]

I agree with WWDude. Don't let the 2nd plumber back in you house .
$400 sounds okay.
The PRV's are not of standard size. The unions and overall length are different for each manufacturer. Get a Wilkens, Very common and reliable brand.
If you put in a double union type you can easily replace it in the future.
The 2nd plumber is partially right. The high pressure did not cause the leak but it did contribute to it.
Hot water lines under a concrete slab have a high failure rate due to the heat reacting with the soil and the expansion and contraction of the pipe.
Cold water lines seems to have a much lower failure rate.

 

[LiQuId]

400, good price. The PRV is a pricey unit itself.

Code Pressures Min 50 Kpa MAx 550 Kpa.

 

[Betadine]

It worked! My nextdoor neighbor had the same problem and didn't know it. His pressure was 100psi. The city water guy came yesterday and found that the fire hydrant was at 100psi. He said our PRV was not working. So my neighbor and I went to the nearest Home Depot. They didn't have the Watts N35B. Instead we got a Wilkins for $89. A few turns of a wrench and a little plumbers compound and the PRV was replaced...in less than 5 min! No leaks! The pressure is now at 50psi. Question: After a quick shower this morning, I checked the pressure gauge on the water heater and it read 65psi. Minutes later it came back down to 50psi. Is this ok? Thanks everyone for your helpful feedback. I saved $300!

 

[Mr_David]

You got lucky that the unions on the watts fit the wilkens.
water pressure will rise when the water heater it heating water. if the rise is excessively high, then an expansion tank would be the next step. But you'll probably not need one.