High water pressure - hot and cold?


  #1  
Old 06-17-07, 08:52 PM
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High water pressure - hot and cold?

A little history...

I have a house built in 1986. The water heater is about 15 years old and needs replacement. However, I've not had any significant issues with it in the 2.5 years I've been in the house.

Sometime last year, I turned off the water supply for the 1/2 bath (2.5BA house) toilet, located downstairs on the same floor as the water heater/furnace (in the garage). When I did (it was about a week before I fixed the goofy handle on the toilet), the water pressure in the house was jacked up -- faucets would blast when first turned on and the pressure was relieved.

When I turned on the supply after getting the parts, the pressure issue went away. Hasn't been back until 2.5 weeks ago.

2.5 weeks ago, I decided to replace the toilet in the same bathroom. I had some trouble getting a replacement and figuring out how to do it (first time), and I just this weekend got it installed. During this time, the water supply was off to the toilet, and the high pressure has been back. I can hear it every time I turn on a faucet, dishwasher, washer, etc. Earlier last week, it was making some pipes bang on one side of the house. That's not going on now.

However, the pressure is still there, even though I've turned back on the supply in the 1/2 bath. The high pressure situation is on all faucets, appliances, etc. And it's hot and cold water. Not one or the other.

I'm going to call a plumber this week if the pressure doesn't die down. I'm curious about the pipes banging (they've done so every once in a while since we moved in, but nothing terribly bad).

Should I use the TPR on the hot water heater? It's not leaking. I also haven't drained/flushed the hot water heater ever. And I haven't done any sort of air purge.

Suggestions are welcome.

Regards,
IronChefMorimoto
 
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Old 06-17-07, 11:43 PM
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This is just a hunch but I'm guessing your municipal water utility (or your house) has a check valve, backflow preventer or non-relieving pressure regulator on the water system.

I'll further guess that the toilet fill valve has had a small leak by for quite some time.

IF these things are true then most likely what is happening is the water heater, as it heats the water is creating the pressure increase. When the leaking toilet fill valve was isolated by closing the supply valve the pressure had no where to go but up.

At this late date flushing the water heater is likely to do more harm than good and since you realize it is on borrowed time it is probably best to not get too rambunctious with it. I would suggest that you buy a new T&P valve and then test the installed valve. It may very well leak after testing and require replacement which is why I recommend buying a replacement before testing.

The cure, and you can do this now or when you replace the heater, is to install an expansion tank on the cold water supply to the heater.
 
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Old 06-18-07, 06:01 AM
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The toilet supply line and valve didn't show any indication of a leak, but the tank was leaking, hence the replacement toilet (it was a cheapo apartment grade toilet anyway). Last year, when I shut the supply line off, the flapper wasn't closing all the way (bum handle). No leaks then on the supply line or supply line valve.

Is there anything that I can do, before calling a plumber, to check the water heater? Or the supply line to the toilet? The new supply line isn't leaking, nor is the supply line valve. I also didn't see any indication of leaks around the water heater or near the TPR on top of the water heater.

That said, what possible problems could I run into by releasing the TPR? Or, heck, even doing a flush or drain of the water heater (since it's probably not been done in years)? I'm suspecting, given your tone, that something that's close to "giving out" might take the opportunity to do so. Lemme know.

Any additional troubleshooting tips are very welcome.

Regards,
IronChefMorimoto
 
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Old 06-18-07, 06:04 AM
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Also, does the fact that the high water pressure condition subsides immediately when using water anywhere in the house play into this situation? With it not being a constant high water pressure situation?

Thanks,
IronChefMorimoto
 
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Old 06-18-07, 12:20 PM
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The fact that the flush valve (flapper) in the toilet was leaking is the reason that the pressure did not build up when the toilet water supply was on. I didn't mean that the valve at the wall or the connecting tubing / hose was leaking external to the toilet.

Your symptoms are classic of a "closed" water system. Years ago almost all municipal water systems were such that any increase in the pressure inside a house (such as you have experienced) simply "traveled backward" to the water main in the street. Today there are one-way (check) valves, backflow preventers and pressure reducing valves installed that will not allow the backward flow. The result is an increase (temporary) of the pressure in the house when the water heater heats up a large quantity of water.

Your problem is more obvious an hour or so after using a large quantity of hot water, right?

This problem, and the installation of an expansion tank has been covered in some detail in the water heater section of the forum.

Since the T&P valve on your water heater has not been tested on a regular basis it could fail to close if you test it now or it could fail to open at all. T&P valves have the test handle on them for a reason and they should be tested at least every six months, or better, every three months. It is not necessary to test them any more often than quarterly and doing so will lead to premature failure. I like to have a spare T&P valve on hand so that if it fails during a test I can immediately replace it. They cost less than $10. Hopefully the T&P valve discharge is plumbed to a safe point to allow a quantity of water to be expelled without any damage to the area.

To test the valve, pull the handle smartly to the full open position and let the water flow for a second or two and then release the handle. Do not "tease" the handle partly open as that often will allow a piece of rust or scale to prevent the valve from fully closing when you release the test handle. If the valve leaks after the test (a little dribble for a minute is normal but it should comepletely stop after a minute) then pull the handle and let it flow for several seconds before releasing. If it still leaks it will need to be replaced. Absolutely NEVER install a plug or cap on the outlet of the T&P valve at any time, even for just a short period of time. A water heater without a functioning T&P valve is a time bomb and is quite capable of destroying the house and killing people.

If you have a gas-fired water heater it is well past its normal lifespan. Gas water heaters have a "normal" life of eight to ten years although any one particular heater may last well beyond the typical lifespan. Electric water heaters are a bit longer lived and depending on the water conditions and maintenance (flushing) may last for more than twenty years.

The problem with flushing a water heater that has not been flushed for quite some time (years) is that often sediment and scale could be sealing a minor leak and flushing will disturb this sediment and scale leaving you with a leaking tank where it did not leak prior to the flushing. This is more common with a gas-fired heater.


As long as your pressure build-up does not cause the T&P valve to open (assuming it is operational) the pressure build-up is more a nuisance than a real problem. I would test, and if necessary, replace the T&P valve today. I would also plan on replacing the water heater and adding an expansion tank in the near future.
 
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Old 06-18-07, 12:47 PM
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Furd -- thanks for the information.

You asked if the problem with the high pressure was more obvious an hour after using hot water. Actually -- it's not. It's constant pressure when ANY faucet is turned on after even just a few minutes. And that's cold OR hot water -- same effect either way.

A few questions about the T&P test...

First, the replacement valve -- it can be purchased at a big box home improvement store? Home Depot or Lowes? And it would be a universal replacement for an old Rheem gas water heater?

Secondly, I'm 100% sure that there's a discharge pipe out behind the garage -- white PVC that matches up with the pipe near the T&P valve on the water heater.

Third, safety things -- if I pull up the T&P valve on the hot water heater, should there be a bucket behind the garage to catch the water? I think my A/C condenser is positioned directly under it. Also, should I wear gloves? Will there be any dangerous steam/hot water discharge around the valve itself?

Finally, you noted that, as long as the T&P valve isn't opening of its own accord, the pressure is a nuisance. Is there any IMMEDIATE cause for concern with regards to appliances? Is the pressure going to damage the dishwasher, washer or refrigerator? Or the innards of the new toilet I installed?

Thanks again for the input -- ALL very helpful.

Regards,
IronChefMorimoto
 
  #7  
Old 06-18-07, 04:54 PM
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"It's constant pressure when ANY faucet is turned on after even just a few minutes."

That little bit of information puts a different light on the subject.

That sounds like you do indeed have a pressure regulating valve (PRV) installed on the water piping coming into your home. It will look similar to this:

http://www.plumbersurplus.com/images/prod/1/03846.jpg

What this device does is to reduce the higher pressure water from the street to a lower pressure to be used in the house. They sometimes leak internally and allow the water pressure to rise to that of the street pressure. When you open a faucet in the house the flow from that faucet is greater than the leak flow and so the PRV seems to act as it should. Of course as soon as you close the faucet the leak will again cause the pressure to rise.

PRV's can be rebuilt but the repair kit is often close to the price of a new PRV and the rebuild process is not always successful along with being potentially dangerous to the person doing the work. I recommend replacing the PRV rather than rebuilding.

You may desire to temporarily install a pressure gauge like this:

http://www.premium-water-filters.com/images/WaterTestGaugeWPTG_225.jpg

to the drain on your water heater or to one of the faucets on your clothes washer. I couldn't find a picture but the better ones have a resettable hand (usually red) that will hold at the highest pressure until manually reset. They cost less that $12 at Lowes or Home Depot. Install the gauge and turn the faucet on. The pressure will go up. Now go turn on a faucet somewhere else in the house, leave it on and check the pressure gauge. It will be reading lower. Turn on a few more faucets (leaving the first running) so that you have multiple faucets running and check the gauge. If the pressure with multiple faucets running is only slightly below the pressure of only one faucet running then that pretty much defines an leaking PRV.


Note that in my previous post that although I referenced the water heater as the cause it would have still affected the pressure in both hot and cold water piping.


Temperature & Pressure safety valves.
Yes, you can purchase the new T&P valve at Lowes or Home Depot, or even your local hardware store. Perhaps even a general merchandise department store would have them in the plumbing section. They are pretty much universal with a 3/4 inch male pipe thread on the inlet side and a 3/4 inch female pipe thread on the outlet. The inlet will also have a "stem" thermostat about 1/4 inch in diameter and about 4 to 6 inches long. This is a pretty typical one alongside the box it comes in:

http://images.lowes.com/product/converted/098268/098268214673md.jpg

They are available in boxes, in poly bags, carded and loose. The loose ones are usually less expensive than those in boxes although they are functionally the same. I think the one I bought a couple of months ago was less than $6.

Pulling the test handle may release some hot water around the valve (assuming the discharge piping is intact) so it might be a good idea to wear a heavy glove when you try it. If the discharge piping is going to spray onto your A/C condensing unit then absolutely put a bucket under the discharge pipe. This pipe should lead to a place where any discharge would cause no damage. Be sure that line behind the garage is indeed connected to the T&P valve and is not a drain from your A/C inside coil. Plumbing codes requie the discharge line from a T&P valve be of a material that will withstand the full pressure and temperature of the hot water system and PVC does not normally qualifiy. It could be the discharge piping was done without code approval.


Normal water pressures for a house are generally 60 to 70 psi. If you get your gauge and the pressure with no water flowing (the static pressure) is less than 100 psi it is not, in my opinion, an immediate concern and you can replace the PRV when it is convenient rather than immediately. Higher pressures ARE hard on things like washing maching hoses and faucet (and toilet) connector hoses. The sooner you get the pressure back to "normal" the better things will be.

There is a slim chance that the PRV is located in the street and is the property of the water utility and they will repair or replace it for free. This is rare but a call to the utility will answer the question.
 
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Old 06-18-07, 05:31 PM
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This is all good information, Furd. Thank you.

I'm curious -- about the time the water pressure went up (perhaps erroneously attributed to the toilet supply valve being cut off), a lot of watering bans went into effect in my area (Atlanta, GA). Would that ALSO contribute more to a PRV leak? More static pressure at the street due to lack of use?

Dumb question, I'm sure, but I figured I'd ask.

IronChefMorimoto
 
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Old 06-18-07, 06:02 PM
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The only "dumb question" is the one not asked.

The internal parts of PRVs are constantly moving and they do wear out. The incoming water also has a small percentage of tiny pieces of dirt and metal that can erode the internal parts of the PRV.

Could the watering ban have been contributory to the PRV problem? Maybe, but I think it is more likely normal wear and tear.
 
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Old 06-20-07, 06:47 PM
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I FINALLY bought a WATTS pressure gauge at Lowes tonight. It was dark when I got home and it was dark (it's amazing how long the self checkout line at Wal-Mart, the 2nd stop tonight, can take when people don't know what they're doing). Rather than try and purge the water heater with the TPR valve in the dark, I decided to ONLY test the pressure.

I tested the pressure at the front and back outdoor water spigots. I'm not sure if I did something wrong, but I got 140psi off both. And turning on 1-2 taps in the house only reduced the pressure minimally. 10psi at most.

I DID take a flashlight out to the back of the garage, and there IS a metal pipe coming out and pointing straight down behind the garage -- it's not PVC, as I suspected before.

Should I even bother opening the TPR valve? Or just go ahead and call the plumber with this kind of pressure in the house?

Please note -- when the pressure died down, the appliances and faucets operated just as they have normally BEFORE I started experiencing this high pressure water condition (after turning off the downstairs 1/2 bath toilet supply 3 weeks ago). That supply is back on too -- to my new Kohler Wellworth.

Please chime in, Furd, or anyone else.

Thanks,
IronChefMorimoto
 
  #11  
Old 06-20-07, 08:37 PM
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Sometimes the outside hose bibbs (faucets) are connected before the pressure reducing valve (PRV) and will show a much higher pressure than is inside the house. Since the pressure drop with the inside faucets running (you did leave them running when you went back outside to check the gauge, didn't you?) was minimal I suspect that the outside faucets are piped in thins manner. You really need to check the water pressure at the laundry connection or the drain on the water heater.

Anyway, this makes it an almost certainty that you have a PRV inside your house. It is most likely near where the main water shutoff valve inside the house is located.

No, I wouldn't suggest testing the T&P valve on the water heater under this condition. With the pressure sitting at 140 the T&P valve may not close properly and even a new valve may be troublesome as they are supposed to open at 150. You really need to get that PRV replaced. If you are not handy with plumbing tools (it can't be done with a 10 inch chef's knife) then a call to the plumber is in order.

It isn't a hard job, provided it was properly installed with union fittings originally but it is a bit more involved than installing a sink faucet.

p.s. Are you really the iron chef?
 
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Old 06-20-07, 09:27 PM
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OK -- I went back and hooked the gauge up to the water heater drain.

At the time, I was running both the dishwasher and the washer. I knew that, when they stopped filling/rinsing, I'd get the high pressure reading off the gauge. Initially, I was happy -- it was only about 40psi...until they stopped doing their thing. THEN, I got this reading...

http://ebay.mrbdesign.com/plumbing_1.png

Looks like a high pressure, inside, of 140psi. It reads 40psi to about 60psi when water is running, so it's not like the pressure is constantly high when it's running. Don't if that's good or not. It's sure as heck pushing on things, though.

Here's my water cutoff valve and (FINALLY FOUND THE LITTLE BUGGAR) the PRV...

http://ebay.mrbdesign.com/plumbing_2.png

From left to right (looking at the back wall of my garage), it's...

1. Rheem hot water heater on wooden support box
2. Trane XR80 furnace
3. PRV and shutoff valve between wall and furnace (as seen above)

Here's a closeup of the PRV (no leaking visible)...

http://ebay.mrbdesign.com/plumbing_3.png

I have no clue how I'd ever replace that. There's about 8" to work with in that space -- between the wall and the furnace.

Questions...

1. Is it bad to leave the pressure gauge on while I'm not at home? On the hot water heater drain valve?

2. Should I call the city FIRST and have them check stuff at the street? Or do I assume that it's something in my house?

3. Will a plumber with a fat ass fit in that space to repair the PRV?

IronChefMorimoto
 
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Old 06-20-07, 11:39 PM
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Your tests with the pressure gauge and the picture of your incoming water and PRV confirm that it is internal leakage of the PRV.

It is best to remove the pressure gauge from your water heater. Leaving it connected for a day or two probably won't hurt anything. Long term problem would be if the gauge broke while the drain valve was open and water would flow until someone saw it and closed the drain.

No point in calling the city because the PRV is definitely the problem and it is inside your house making it your problem.

I agree that is a gawdawful place to get to in order to do any work. Best to tell the plumbing company that it is in such close quarters when you call.


Here is a site (pdf file) that explains a bit how a PRV works. Yours is leaking internally past the valve shown at the bottom of the illustration just above the smaller red spring.

http://www.boltonpoint.org/PDFs/PressureRegulatorsQ&A.pdf
 
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Old 06-21-07, 06:28 AM
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Plumber has been called and should arrive here by about 10am this morning.

Is there anything I should get him to check, in addition to the PRV? Water heater situation? Or is he just going to tell me to replace it as soon as I can?

I got nervous about the gauge and removed it last night at about 3am. It was hard to remove with the pressure built up.

IronChefMorimoto
 
  #15  
Old 06-21-07, 08:48 AM
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Have the plumber give a quote on replacing the water heater. If you like the work he does on the PRV and the quote on the water heater seems reasonable let him schedule a replacement.

It goes without saying that replacing a water heater before it leaks is always preferable to waiting until it does leak and becomes an emergency.
 
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Old 06-21-07, 09:08 AM
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$582 later...and I have a new PRV.

Guy got in here before I could call back about the space constraints. He goes into the garage, after he agrees with what we've discussed here, and goes..."Oh, damn dude. Damn, dude -- I'm really sorry to tell you this...but...I'm gonna have to cut out your wall."

The ONLY way he could get between the wall and the furnace to remove the PRV was to cut out a 2'x2' section of wall in my breakfast nook (to the left of the laundry cubby). AND, he couldn't repair it -- "We don't do sheetrock repairs, sir. I can only replace the plumbing hardware."

Anyway -- I have a monster (relative to the unit) new PRV, and I can tell the difference in the water pressure. He, too, advised me not to touch anything on the Rheem water heater. He dated it original to the house -- June 1986 manufacturing date. I should take it out for its first beer -- it turned 21 this month.

I will be calling a sheetrock guy to come in, frame in a door (plumber's recommendation) in the hole in our breakfast nook, and clean up the wall. The door was recommended for getting access to the PRV, the shutoff valve, and the spigot shutoff valves. He (the plumber) was just shaking his head when he saw it.

$1000 to $1200 for a 40 gallon replacement water heater + expansion tank (required by code), BTW. $150 more if we want a 50 gallon model.

IronChefMorimoto
 
  #17  
Old 06-21-07, 09:36 AM
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Yeah, the plumber that originally put those pipes and valves in should be shot. Sorry that it was such an expensive job and not even finished yet.

The price for the water heater sounds reasonable for a heater with an eight to ten-year guarantee.
 
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Old 06-21-07, 11:48 AM
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Question is -- did I overpay for this job? Given that the sheetrock was repaired? This plumbing company gives me a 15% discount 'cause it's tied to my HVAC unit (2 years old -- new install) maintenance contract. Mr. Plumber -- bought by CoolRay here in Atlanta about 2 years ago, I think. Flat rate pricing. It went from about $450 to $582 because the guy was working in a tight space...?

BTW -- he would've charged $900 to bury a box next to the city meter at the street and install the PRV there.

IronChefMorimoto
 
  #19  
Old 06-21-07, 04:33 PM
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I don't know if you were overcharged. The PRV typically will cost somewhere between $50 and $100 from the plumbing supply and the plumbing company will typically mark this up by 20% to 40%. The plumbing company probably has a set charge per job to cover some of the overhead including insurance warehouse taxes and everything else that goes along with running a business. This may be somewhere between $50 and $100. Then comes the actual work. In order to make any money the plumbing company probably has to charge somewhere in the neighborhood of $80 to $120 an hour for the labor.

Understand that the person doing the work does not receive but 25% to 35% of the labor charged to the customer for his wages.

I don't like flat-rate pricing because a competent person, no matter what the craft, (auto mechanic, plumber, electrician, etc.) can usually do the job in less time than the flat-rate time allowed for any particular job. In these cases the customer ends up paying more for labor on a per-hour basis. Sometimes, like in the case of a person new to the job or sometimes a job like yours that entails additional work, the customer will benefit from flat-rate pricing but that is not too common.

Since an up-charge was added to your bill for difficult location you did not benefit from flat-rate pricing. Your bill may have been a bit on the high side but I don't think it was excessive.
 
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Old 07-02-07, 07:33 AM
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Well -- looks like my pressure is still going up -- to around 140psi.

It's only occasionally -- usually AFTER using significant amounts of hot water, which, per the earlier portion of this thread, is probably due to...? The hot water heater not having an expansion tank?

When the pressure goes down, it hovers around 40psi - 50psi. It was up around 90psi after showers this morning.

I'll be calling them back to get an estimate on a new water heater and expansion tank this week.

BTW -- my bill was reduced by about $100 due to a pricing error on their end. Only turned out to be about $490.

IronChefMorimoto
 
  #21  
Old 07-02-07, 10:01 PM
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When the pressure is high after the water heater recovers does it drop to normal immediately by opening a faucet (either hot or cold) and running just a small amount of water?

If yes, then it is the expansion of the water as it is heated. The proper sized expansion tank should cure this.
 
 

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