Pressure Reducing Valve really necessary?

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My hot water heater is a 21 year old Rheem. It still works and does not leak. I am planning on replacing it due to the age. I am planning on having an AO Smith installed.
Today, the technician who gave me an estmate hooked up some type of gauge to one of the garden hose faucets, and he told me that the pressure he measured was 115 PSI. My townhouse does not have a PRV valve. He said that if my pressure was over 125 I would be required to have a PRV and expansion tank installed in order for the heater to be replaced. He says that my pressure is high, and if I don't want a PRV and expansion tank installed, I still have to sign something indicating I am aware of the high pressure and that it is possible the T&P valve could drip as a result of the high pressure.
He claims the newer tanks are insulated with foam and the insulation is tighter which means the water heater tank itself can't expand as much as older tanks could. (not sure I'm buying that)
QUESTION: If this house is 21 years old, and my old heater is 21 years old, and there hasn't been a problem as a result of the higher than normal pressure, is it really worth paying another $400 to have the PRV and expansion tank installed with the new heater? (My mom lives in same development and does not have a PRV either. A few other townhouses in my development that I have seen don't have one either. I believe one of my neighbors does have one though.)
Thanks,
Jay
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I would check the pressure myself. 115psi is very high. Mine was 90psi and I installed a prv to bring it down to a normal 55psi. High pressure is asking for problems.
My pvr allows backflow if the pressure exceeds the supply pressure and I don't have a backflow prevention valve at the supply; so I didn't need an expansion tank. You might, depending on your system; especially with the 115psi supply.
You never had a problem because you were lucky. Don't press it.
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Yep. A home inspector; in his report, said pressure was to high and that I needed a PRV.
I took several readings over a day to find the average pressure. Keeping in mind (city water) the pressures dropped in the area after folks came home and started using water for meals, bathing, etc...
I even challenged the inspector's gauge about accuracy. We were only talking little difference so the house would sell....
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In the area where I live, the hose faucet on the front of homes does not run through the PRV or through the cutoff valve for the whole home. Double check your pressure on another hose faucet. You need that PRV because incoming water pressure may spike occaisionally. To get back to the original thread, if I had a 21 year old water heater and money was not an issue, I would replace it now. Flooded houses are no fun and a new heater will be much more efficient.
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On Thu, 24 Jul 2008 14:55:37 -0700 (PDT), greg2468

I bet his local Permit/Code Dept can tell the OP the real essentials.
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I just bought a Watts pressure gauge at home depot and hooked it up myself. The highest reading I got (from leaving it on maybe as long as 5 minutes) was 90 PSI. Granted it's still high, but a heck of a lot lower than 115. I will reconnect it at various times (such as later tonight around 11pm) to see if the levels change.
I'm a lot more confortable without the PRV if it turns out the usual overall level is 90 rather than 115. Question is why the plumber got a reading of 115. I hope is reading was wrong.
Jeff

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Question is why the plumber got a reading of 115. I hope is reading was wrong. --------------------------- Frankly, I think the guy is either a flake or a fraud. Water heater never expanded, to claim they did is ridiculous. I doubt your water pressure was ever 115psi.
Personally I would not want 90 psi, but then I don't have to pay a plumber to put in a valve.
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If he's in a low part of his system, then 115 would be a very real possibility. I'm far from being on the low end of my system and mine is 110. These water companies are maxing out their systems trying tokeep up with demand with extra pressure. Over at another one of our houses, the 270 degree sweep gauge that goes to 100 went all the way around to the zero peg.
steve

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Also, I am leery about the idea that the installer would be making me sign something saying that I am aware that water pressure is above a certain level and that **I AGREE** that if the T&P valve drips I would need to get a PRV valve before the installer would address the issue of drip. I could sign something saying that I am aware the water pressure is above 80, but I am **leery of agreeing** that I should have to install a PRV valve before the installer would address the issue of a drip. (MY Reading, so far, says the water pressure is around 90. ) Unless the manufuturer requires that I sign such an agreement (and I don't see any evidence of that), or unless some state law requires I agree to that, then why should I sign such an agreement? Is signing something like that standard practice in NJ?
Thanks,
Jay
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AT 115 you should have one. You could however put it in yourself for about $40.
s

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On Jul 24, 3:22pm, "Steve Barker DLT"

Yep. I find the OPs post to be suspect. Either he misunderstood the plumber or the plumber is scamming bit time. There is no way a PRV and expansion tank would cosst $400 even if installed by a plumber. The tank being unable to expand due to new type consstruction is the purest BS. Even old typ tanks never expanded enough to accomodate excessive pressure and the foam packing fro damn sure won't have any effect either way on tank expansion which is essentially nill in any case.
Harry K
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I'm merely repeating what the plumber told me regarding the new tanks versus the old tanks.
Anyway, I've had the new Watts pressure gauge, that I just bought, connected to my hose faucet for an hour 11:05 pm to 12:05 am. The pressure did touch as high as 98 or 99, according to the red "memory" needle, but it never got over 100. Also, the pressure did not appear to staying up at those levels (when I would go out periodically and observe the meter for a few minutes at a time.) It seemed that pressure went above 90 it did not stay there very long. There were times I would see the needle stay around the 90 level, but it would hover around the 80 level just as frequently if not moreso than hovering around 90. I'm going to leave the pressure gauge connected overnight to see how high the red "memory" needle reaches.
So far I'm getting the impression that my water pressure is relatively high, but is not extraordinarily high. I'm not seeing any reason why I should have to sign anything indicating that if the T&P valve drips that the water pressure will be deemed the cause of the drip until I have a PRV valve installed. Is that standard practice?

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It sounds like he is trying to void the warantee by having you sign the statement. I have never heard of that being done. Call a different plumber and see what they do.
Even 90 without the spikes is too high by far for normal household appliances. That is hard on all fixtures and especially valves such as in washing machines and dish washers, sprinkler systems.
The $400 to install one plus surge tank seems high to me.
Harry K
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So far I've had the gauge connected for over 12 hours. I've still yet seen the red memory needle get above around 98, and it didn't stay near there long. The pressure is probably averaging 85 or maybe upper 80s. It's higher than normal, but not extraordinarily high. I'm wondering why they can't install a Watts PRV valve that allows backflow rather than bothering with an expansion tank? According to Watts the ones with a B suffix in the model number allow backflow from thermal expansion.

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wrote:

Totally pointless. The backflow may be prevented at your meter, either now or in the future. Put in the expansion tank; take it from somebody who's been there and had the leaks.
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The meter doesn't prevent backflow. I've seen the meter run backwards.

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wrote:

The meter doesn't prevent backflow yet. Meters can be changed, and new ones may prevent backflow. In fact, I suspect it is a requirement these days.
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You seem to be trying to rationalize your decision not to spend the extra money to put in a PRV and tank. Whether it's 115 or 100 it's still high. You seem to think that a leak will occur at an average pressure reading. That is not how it works. Or maybe you're hoping that a low reading will convince the leak not to happen at all?
You are asking questions that people in your location are best able to answer. Our water district has some odd requirements and it is pointless to argue with them. Why not pick up the phone and call another plumber? If you don't have one you trust, ask neighbors and friends for some names.
R
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Granted the pressure is high if it can briefly get to 100. However, given that the water heater in my townhouse has lasted 21 years without a leak, would it be unreasonable for me to believe that the water pressure really isn't a problem? My mom lives in the same development and she does not have a PRV valve either. I only know of one neighbor that has one.
Nobody is requiring that I install a PRV valve. It is a question of whether or not it is a good idea to install or a waste of money.

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