# Fixed Toilet, now high water pressure?



## turtle_rouge (Jun 21, 2010)

I recently replaced the parts inside of our toilet tank. It had been running ever so slightly since we bought the house. Now that the toilet is not leaking, our faucets occasionally have a moderate burst of pressure when they are first turned on and then they go back to their normal flow. What is going on?


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## woodchuck (Jun 21, 2010)

Sounds like air in the water line and it settles at the highest points which are the faucets. Could be from work on the water line down the road etc. It takes a long time to get it all out sometime.


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## Redwood (Jun 22, 2010)

My guess is that you have a Pressure Reducing Valve that has failed or, a Thermal Expansion Tank on a water heater that has failed...

The leaking toilet bled off the excess pressure...


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## Nestor_Kelebay (Jun 22, 2010)

My guess would be that your water meter has been replaced by your local municipality.

You see, older water meters used to allow for backflow through the water meter.  So, when cold water was heated in the water heater, the expansion of the water would result in a tiny bit of back flow through the water meter.

However, there's been a great effort to prevent this kind of backflow because it could result in "Grey" water getting back into the water distribution system and coming out somewhere else, like into your glass of drinking water.  So, nowadays all water meters have check valves that prevent that backflow.

So, if you don't have an expansion tank on your water supply piping, that burst of pressure is probably just due to the expansion of cold water in your water heater.

So, probably best to take a hammer to them new parts in your toilet tank until the toilet leaks again.  

As Redwood says, the problem was always there, it's just that the leaking toilet bled off that pressure.


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## turtle_rouge (Jun 22, 2010)

Those are the two things I was worried about, Redwood. That was all I could find out from Google and I was just hoping it wasn't true. 

I looked at the hotwater heater yesterday. The pressure relief valve appears to be working fine. I think.... It moves up and down. There is a tube attached to it that goes off behind the water heater. I have no idea what it connects to. I am hoping it drains somewhere other than the floor... 

I also looked for a pressure reducing valve and couldn't find one. There wasn't one just off the meter at the street. And, our water shut off is apparently outside, buried under 6 inches of dirt. I dug it up and didn't find anything past the knob. I'm not saying there isn't one, I was just only willing to dig so deep into that stupid little hole with my plastic spoon at that moment... I am guessing it is a bad thing that my main water shut off is buried outside (Is this normal? Do we need to dig it up and insulate it with something easier to remove than dirt?). 

Is there a way I can tell for sure if it is the hot water heater or the elusive pressure reducing valve instead?


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## turtle_rouge (Jun 22, 2010)

Ah, Nestor, you are probably correct. Our water meter was replaced about 6 months ago (yes, sadly, the toilet had been leaking that long...). 

So, do we need to install an expansion tank or is it okay? It is not a huge rush of water, just 1-2 seconds of an increase in volume. I am guessing if we are going to be out for any amount of time, it would be a good idea to let a faucet drip. But, for just daily use, is it alright to have a little pressure build? And, why is the pressure relief valve in the hotwater tank not taking care of this?


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## turtle_rouge (Jun 22, 2010)

Okay, awesome! I just looked up the expansion tank. I can totally install that. Whew! I am so glad that it is not a more major problem. 

I am still wondering though, probably a stupid question, but why does the pressure relief valve not take care of this problem?


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## handyguys (Jun 22, 2010)

The T&P valve is to prevent catastrophic failure of the water heater. Yes, that pipe probably just goes to the floor, best case into a pump pit or floor drain. The expansion tank essentially eases out the pressure fluctuations. Here are a couple pictures.


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## Redwood (Jun 22, 2010)

If the new water meter has a check valve it creates a closed system where the thermal expansion of water being heated in the water heater will create a high pressure burst.

If you let off the high pressure burst and the water heater is not reheating then later check to see if the burst is still present it will answer some questions.

If the burst is not present then it is thermal expansion....

If it is present then there is probably a PRV hidden somewhere that has failed...

In either case you still will want an expansion tank.
If you are installing the expansion tank in a horizontal position like the ones shown in the picture posted by Handy Guys make sure the tank is supported. At some point the bladder in the tank will fail and the tank will become waterlogged. When it does the tank will be quite heavy and require support to keep it from breaking off.


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## Nestor_Kelebay (Jun 23, 2010)

Turtle Rouge:

     Another thought...

Another thing to note is whether or not your PRV has a large brass knurled or hex nut on the bottom.  On the PRV's on hot water heating systems, there will typically be a brass or stainless strainer screen in the PRV that can be replaced by removing that large knurled or hex nut.  (And, it's NORMAL for newbie homeowners to start fiddling with the pressure setting on their PRV when it's not maintaining the heating system pressure only to discover that the problem was a clogged strainer screen.)

What's crossing my mind is that if your PRV has a clogged strainer screen, then the "burst of pressure" you're experiencing may be what the pressure in your water supply system should normally be, and the lower pressure afterwards may simply be due to the lower flow rate through a partially clogged strainer screen.

For example, if you look at this Watts pressure reducing valve:






The cutaway view below reveals that the knurled knob on the upstream end of the PRV is there to allow removal of the strainer screen for cleaning.  All the water flows through that strainer screen before flowing through the PRV and into your house.  My personal experience has been that most of the problems I have with leaking faucets is the result of sand and hard dirt like metal filings in the water coming into the building.  If your PRV has a strainer on it, (and I expect it should) then I'd also expect that screen would need to be cleaned periodically.  It's common for hot water heating sytem PRV's to have their screens clog up, so I would expect the same thing from the PRV on a house's water supply piping.






Also, here's what I consider to be a good idea...

On the pressure reducing valve to my hot water heating system boiler, within 2 feet downstream of that PRV I have both a tee with a pressure gauge and a ball valve with a drain on it on the upstream side.  That arrangement allows me to close the ball valve and adjust the setting of the PRV very quickly and accurately because the 2 feet of pipe downstream of the PRV pressures up very quickly as water flows into it.  Once I adjust the PRV to the correct pressure with the ball valve closed, I can open the ball valve and have confidence that the whole heating system will be filled to that same pressure over the next few hours or so.  That's why I set it up like that.

If you have a PRV on your house's water supply piping, you might want to put the same kind of piping in place.  That would let you check to see what pressure the PRV is set at, and whether or not it's maintaining that pressure when you open a faucet.


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## Redwood (Jun 23, 2010)

Actually the burst of pressure is not caused by a clogged filter screen but rather a PRV that does not shut off completely like a dripping faucet it allows the system to over pressure 1 drip at a time until it builds to a noticeable level...


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## Nestor_Kelebay (Jun 23, 2010)

Then Turtle Rouge should be aware that there's a very good chance he would be able to buy an overhaul kit for his PRV and fix it him/herself.

I know that I can buy overhaul kits for Watts pressure reducing valves.  That kit comes with a new diaphragm, seat gasket, disk (which holds the seat gasket in place), screw (which holds the disk in place), strainer screen, strainer nut and strainer nut gasket.  And, of course, there'll be printed literature that comes in the kit that explains how to go about replacing the parts.  And that kit cost me about $25 every bit of 10 years ago.

If I were turtle rouge, I'd find the name of the manufacturer on the PRV, phone around to the plumbing wholesalers to find out who the local sales rep or agency for that manufacturer is, and find out from that rep or agent whether an overhaul kit is available.  I expect most plumbing wholesalers will order it and sell it to him if he pays cash since they do for that oddball kind of stuff up here.

If it turns out the problem isn't just expansion in the water heater, it'd be worthwhile trying to fix the PRV him/herself before hiring someone to replace it.


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## Redwood (Jun 23, 2010)

I would replace rather than overhaul a PRV...

Unless of course you are a DIYer that likes to Waste Time & Money with very limited success in the results...

If a rebuild kit cost $25 10 years ago, and I can buy a new PRV for $43 I fail to see any logic in repairing especially when there is no guarantee a repair will work....

http://www.google.com/products/cata...og_result&ct=result&resnum=3&ved=0CCoQ8wIwAg#

See my Logic?


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## Nestor_Kelebay (Jun 26, 2010)

The price on that PRV is suspiciously low.

I can't help thinking that a $43 price on a new PRV is a "loss leader".  The company sells some items at a loss to convince customers that all it's prices are really low so they'll buy more.  The company recoups it's loss on first item by the profit it makes on the other items.

Still, if he/she can buy a new PRV for less than $60 including taxes and shipping, replacing the PRV would be an economical option too.


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## Redwood (Jun 26, 2010)

I don't pay much more than that at the local supply house...


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