# Water pressure and Pex piping



## mainstreetprod (Jan 16, 2009)

In another thread it was determined that I have expansion type Pex in my home. In two years there have been two failures, pipe blew off the fitting,
once under the home and once under the bathroom sink. It occured to me that the water pressure might be high so I checked it with a gauge. It is
80 with the water off and 75 with a sink running. To try to reduce the pressure I unscrewed the adjustment screw on the regulator as far as it would go (about a turn and a half more). It had no effect that I could tell.
The home and the regulator are only two years old.

1) Is 75 pounds enough pressure to cause Pex to blow off the fitting?

2) Should I replace the regulator to try to drop the pressure more?


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## DangerMouse (Jul 17, 2008)

It occured to you that the water pressure might be high? 
didn't the missing skin from your back after that last shower tell you something?
methinks the pressure is a bit high for home use.....

DM


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## zosoplumber (Nov 21, 2008)

In most areas, the inspector will not pass a rough in inspection unless the plumber puts a pressure test on the water lines, in my area you have to have atleast 100psi to pass, now I have seen way more then 100psi, 150-200. It should hold up I believe the rating printed on the pipe says 100psi at 180 degeres. The problem you have with the 80psi, is in your fixtures. I still would check all rings possible for faulty crimpers.


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## zosoplumber (Nov 21, 2008)

yes, and I would replace reducer if theres no way of fixing it.


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## mainstreetprod (Jan 16, 2009)

DangerMouse said:


> It occured to you that the water pressure might be high?
> didn't the missing skin from your back after that last shower tell you something?
> methinks the pressure is a bit high for home use.....
> 
> DM


Without the test with the gauge, I would not have guessed the pressure was
higher than normal. Shower is not like pressure in most motels, and water
from faucets seems normal.


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## AllanJ (Nov 24, 2007)

(copied from another post)
Not sure what the effects of water hammer are on Pex systems. I would be suspicious of joints "blowing" apart.


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## II Weeks (Jan 6, 2009)

80 pounds?

sounds high to me. I think my area water pressure is at 45 pounds but even still, the fitting should hold at 80.


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## Bob Mariani (Dec 1, 2008)

AllanJ said:


> (copied from another post)
> Not sure what the effects of water hammer are on Pex systems. I would be suspicious of joints "blowing" apart.


I had water well regulator problems in the past and the pressure was way to high. Also had water hammer issues. And the entire house is PEX. Neither issue will cause any concerns with the PEX connections as long as they are correctly crimped.


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## mainstreetprod (Jan 16, 2009)

The system also has a hot water recirculation pump. I've read that they can eventually cause pinhole leaks in copper pipe due to water velocity at the joints or something like that. What are the effects on a Pex system if any?


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## Bob Mariani (Dec 1, 2008)

Should not be a problem using PEX. One advantage with this is fewer fittings. Flow though 3/8" pex is equal to 1/2" copper. But all PEX fittings are not created equal. Use the fittings that match the PEX manufacturer and use a tool that has a positive crimping action. (Will not crimp unless it is the correct connection)


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## 4just1don (Jun 13, 2008)

I may have misunderstood,,,BUT I read you backed OFF your pressure regulator(in other words increased pressure) by backing it off that round and a half,,,try screwing it DOWN to reduce pressure. We dont have those here,,,I may be mistaken,,,but anywhere i reduce pressure its by screwing it IN and cutting flow,or its opening,,,RIGHT???


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## wrangler (Oct 9, 2008)

mainstreetprod said:


> In another thread it was determined that I have expansion type Pex in my home. In two years there have been two failures, pipe blew off the fitting,
> quote]
> 
> As I recall, there was still some question as to what type of fittings you had since there was mention about the use of a ferrule. Did you ever get pics of the failed connections?
> And a question for those of you plumbers that have used alot of diff Pex; can his memory pex fittings be replaced with crimp fittings if neccessary?


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## mainstreetprod (Jan 16, 2009)

RE: Turning right or left to reduce pressure - according to everthing I found on the 'net about typical service line regulators, which have a screw and locknut on top, you turn the screw counterclockwise to reduce pressure. If any
of the regulators are the opposite, please let me know.

RE: the under sink connection, I believe it is this type:

http://www.pexsupply.com/img/categoryImages/Wirsbo Brass Swivel Adapter.jpg


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