# RPZS disc damage



## 422 plumber (Jul 31, 2008)

Check out the damage to these discs, I have never seen this before. There must have been a hella water pressure spike.


----------



## SewerRatz (Apr 25, 2009)

I seen that on rpzs that are online to lawn sprinkler systems. The landscrapers hook up their tow behind compressor to blow the underground lines out. But they do not isolate the RPZ so the back pressure blows the RPZ apart


----------



## 422 plumber (Jul 31, 2008)

These were from a school, with about 90 psi incoming. The pressure never used to be that high, but the city upgraded the water mains and pressure. They need a PRV, but the school board doesn't think so.


----------



## GAN (Jul 10, 2012)

SewerRatz said:


> I seen that on rpzs that are online to lawn sprinkler systems. The landscrapers hook up their tow behind compressor to blow the underground lines out. But they do not isolate the RPZ so the back pressure blows the RPZ apart


Any of these especially if they are on lawn irrigation should have a properly sized expansion tank. Since water does not compress, on a long system with 60psi, it can generate a 600psi wave that hits the valve when solenoids, etc. slam shut.
Generally it is at least ten times the pressure.
Not counting what Sewer Ratz talked about.


----------



## plumbing ninja (Jan 15, 2012)

422 plumber said:


> These were from a school, with about 90 psi incoming. The pressure never used to be that high, but the city upgraded the water mains and pressure. They need a PRV, but the school board doesn't think so.


I'm betting their water consumption has gone up since last year and the difference could of easily covered your fee to buy, fit and commission PRV!

If something goes wrong the system was not designed for the new pressure! Possible premature failure, void of product, plant warranties maybe???


----------



## Mike Rosselli (Aug 15, 2013)

You should whip out your code book and show them max water pressure to building Is 80 psi and the law required PRV! And charge em double for being stupid.

Sent from my iPhone using PlumbingZone


----------



## gilbertjeffrey (Mar 6, 2011)

freezing will do that too.


----------



## justme (Jul 4, 2012)

plumbing ninja said:


> I'm betting their water consumption has gone up since last year and the difference could of easily covered your fee to buy, fit and commission PRV!
> 
> If something goes wrong the system was not designed for the new pressure! Possible premature failure, void of product, plant warranties maybe???


The only way water consumption would go up would be through fixtures without aerator's like janitors sinks or equipment in the kitchen, it wouldn't effect toilets ,lav's, breakroom sink, urinals, showers but it could effect drinking fountain or irrigation .


----------



## Plumberman (Jul 7, 2008)

422 plumber said:


> Check out the damage to these discs, I have never seen this before. There must have been a hella water pressure spike.


I've seen that with a booster pump tied in directly down stream of the backflow with no check installed..

Back pressure when pump cycled was slamming the checks in the backflow.


----------

