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  • Pressure Relief Valve

    Hello guys,
    I am new here and have a question I hope you can help me with. The problem is I have a Watts Pressure Relief valve on my incoming water line and noticed that my pressure when checked at the outside faucet is 92psi. If someone turns on the cold water it drops to the pre set 52psi. I suspect I need a potable water expansion tank as I know the builder did not install one and since the house is only five years old I guess it is a closed system. My questions are:
    1. Do you think it is the valve malfunctioning or a need for a expansion tank?

    2. The lines at the water heater run only up and down not horizontal can a tank be installed in line?

    3. What tank do you guys recommend if needed?

    Thank you in advance for your time and expertise.
    TPS
    Last edited by TPS; 06-30-2008, 10:46 PM.

  • #2
    Re: Pressure Relief Valve

    An expansion tank in conjunction with a PRV is always a good idea, most likely when your water heater kicks on, the mass of the water increases and increases your pressure, PRV's tend to be a one way valve that won't allow the excess pressure to escape into the street main.
    You shouldn't have any trouble having a plumber install one in your situation.

    Comment


    • #3
      Re: Pressure Relief Valve

      Thanks DB, I was told that Watts makes an adjustable pressure relief valve too would that work in lieu of a tank? I have a plumber that is going to check it out for me in a few days, but I like to have some info. as to my options so we can decide on what is best.
      Thanks again-TPS

      Comment


      • #4
        Re: Pressure Relief Valve

        While this won't come cheap you would do well to have 2 expansion tanks. One would be for the water heater only and the other would be installed right after the pressure regulator for your main water system. You would do well to have a pressure relief valve and a pressure gauge installed just before the inlet to the main water system expansion tank. A bladder type tank used for a well and pump system would work nice for this. The outer steel or fiberglass tank is pre charged with compressed air and inside is a heavy duty synthetic bag (bladder) that holds water. This is to keep the water clean and also helps prevent air logging.

        You will want a cross fitting at or near the inlet to the expansion tank so you can install both a pressure relief valve (3/4" set to 75 PSI) and a pressure gauge 0-160 or 0-200 PSI so you can keep watch of your water pressure. It's a good idea to install a 0-300 PSI pressure gauge just before the pressure regulator and to install check valves per code. Another 0-300 PSI gauge would be installed in a special T fitting just after your main water shutoff valve inside your house. This indicates the city water pressure. You might want to have a garden hose bib installed at this location too so you can drain the system and also have good high pressure for blast washing things. The second pressure gauge 0-160 recommended would be show the pressure in your expansion tank on the outlet side of the regulator. Be sure to have ball valves and unions installed so it's easy to close off and remove the pressure regulator later on for servicing it.

        If I can find any good pictures showing what I have in mind, I'll post them here on this thread. Pictures tell the story far better than words can.

        While you'll hate the $$$ to have all of this installed, over time you'll be thankful for the improvements.
        Last edited by Woussko; 07-03-2008, 12:08 AM.

        Comment


        • #5
          Re: Pressure Relief Valve

          Originally posted by TPS View Post
          Hello guys,
          I am new here and have a question I hope you can help me with. The problem is I have a Watts Pressure Relief valve on my incoming water line and noticed that my pressure when checked at the outside faucet is 92psi. If someone turns on the cold water it drops to the pre set 52psi. I suspect I need a potable water expansion tank as I know the builder did not install one and since the house is only five years old I guess it is a closed system. My questions are:
          1. Do you think it is the valve malfunctioning or a need for a expansion tank?

          2. The lines at the water heater run only up and down not horizontal can a tank be installed in line?

          3. What tank do you guys recommend if needed?

          Thank you in advance for your time and expertise.
          TPS
          If you're on city water, Woussko's got it. A tee, valve, well tank. Your 92# is from a spike when you shut off the valve that's running.

          If you're on a well, those newer pumps with the control lights inside and the real small tanks, that run as long as you are running water? I've noticed those tend to run on a little when the water is shut off before the pump shuts down. Probably normal.

          Of course, we're assuming you're talking about a pressure reducing valve, and not a pressure relief valve. Conbraco makes a ball valve I use on the dairies now and then that has a little relief valve built into the side with a barb, you run a little hose from there to a floor drain. Handy little thing to keep those big W/H's from bursting when the expansion tanks give out (which they always do in the dairies for some reason.)
          sigpic3:00, I mean 5:00, and work is done. Time to crack a cold one.

          Comment


          • #6
            Re: Pressure Relief Valve

            Woussko,
            I wish you were the contractor when the fella I bought from built the house! I would like to see the pics if you can get them but from the sound of it I will not have the room to set up like that now. Thanks for the insight and reply.

            Boilerman,
            Good catch I wasn't thinking, yes I did mean a pressure reducing valve. I wonder can those pressure relief valves you were talking about be set at say 80# so that they will drain water/pressure until it normalizes? On the other hand what kind of problem would be encountered if there was a pressure relief valve set at say 80 or 85# where the normal PRV sets on the top of the Hot water heater? Would it just run water all the time? By the way I am on county water system with a septic system. Thanks for the input I really appreciate the replies.
            TPS

            Comment


            • #7
              Re: Pressure Relief Valve

              I believe the ones I use are preset at 125 or 150. Most W/H's are preset at 125 for residential, but the bigger ones you can get 150. You can get
              relief valves in a lot of ranges, but I don't really think that's what you need. Is the hose bibb you got your pressure reading on ahead of the PRV or after it? If you're getting it after, than you might try getting a rebuild kit for the reducing valve.
              sigpic3:00, I mean 5:00, and work is done. Time to crack a cold one.

              Comment


              • #8
                Re: Pressure Relief Valve

                Originally posted by TPS View Post
                Hello guys,
                I am new here and have a question I hope you can help me with. The problem is I have a Watts Pressure Relief valve on my incoming water line and noticed that my pressure when checked at the outside faucet is 92psi. If someone turns on the cold water it drops to the pre set 52psi. I suspect I need a potable water expansion tank as I know the builder did not install one and since the house is only five years old I guess it is a closed system. My questions are:
                1. Do you think it is the valve malfunctioning or a need for a expansion tank?

                2. The lines at the water heater run only up and down not horizontal can a tank be installed in line?

                3. What tank do you guys recommend if needed?

                Thank you in advance for your time and expertise.
                TPS
                By the way, bladder tanks can be installed sideways, but it's not recommended. They get waterlogged in time, and it's a bit of weight for the little nipple that holds them to the pipe. Hang it if you do.
                sigpic3:00, I mean 5:00, and work is done. Time to crack a cold one.

                Comment


                • #9
                  Re: Pressure Relief Valve

                  Boilerman,
                  I was afraid to have a tank mounted sideways anyway, that is why I was thinking some kind of pressure relief valve after the pressure reducing valve and before the hot water heater or even on top of the hot water heater.

                  The hose bibb where I get the reading is after the pressure reducing valve. It reads 92#, when I run water it goes down to 52#. Does that mean there is 40 at the faucet? I am not sure how to interpret that drop, at any rate it creeps back up to 92# and stays there after the water faucet is turned back off.
                  Thanks for the replies and information I am taking it all in and weighing my options you folks have been helpful.
                  Take care-TPS

                  Comment


                  • #10
                    Re: Pressure Relief Valve

                    Originally posted by TPS View Post
                    Boilerman,
                    I was afraid to have a tank mounted sideways anyway, that is why I was thinking some kind of pressure relief valve after the pressure reducing valve and before the hot water heater or even on top of the hot water heater.

                    The hose bibb where I get the reading is after the pressure reducing valve. It reads 92#, when I run water it goes down to 52#. Does that mean there is 40 at the faucet? I am not sure how to interpret that drop, at any rate it creeps back up to 92# and stays there after the water faucet is turned back off.
                    Thanks for the replies and information I am taking it all in and weighing my options you folks have been helpful.
                    Take care-TPS
                    this is not because of thermal expansion. it's because the pressure regulator has a leak that is bypassing. typically it's a small cut in an o-ring or the brass stem that the o-ring rides on. it could also be a small speck of dirt on the washer.

                    yes you can attempt to rebuild the regulator, but on a small unit 3/4''-1'' it's usually better to just replace the worn out regulator.

                    most likely the high pressure before the regulator is 92#. this is not that far above the 80# required for a regulator.

                    the majority of regulators have a thermal bypass feature. which allows for thermal expansion to bypass back to the city main. this is assuming that the water main or meter does not have a check valve/ backflow preventer.

                    it also assumes that the city main is less than the 150# setting on your relief valve.

                    an expansion tank will not cure a bad pressure regulator. it will cure thermal expansion.

                    rick.
                    phoebe it is

                    Comment


                    • #11
                      Re: Pressure Relief Valve

                      Thanks Rick,
                      I have just ordered a Watts 25AUB the one with a Union on each side which will make it easier for me to change in the future. I appreciate all the input and I did not know that the PRV had a way to allow for expanion so now I feel better 'cause it was cramped in the area to do too much. By the way I appreciate all the input in the other areas you guys really do help folks like me. TPS

                      Comment


                      • #12
                        Re: Pressure Relief Valve

                        TPS

                        If you live in the country and are on a septic system are you sure that you aren't getting water from a well with a pump? The pump may be a submersible type installed in the well casing near the bottom. Somewhere near your main water inlet you would see a control box with pressure switch and some electric wiring. I have heard of areas with pressurized community water service that's piped to each customer and where they don't have sewers but such is rare and especially if you're out in the country with several acres of land or more.

                        If you do have a well and pump, you might have a water logged tank or one that's too small. Why there would be a pressure regulator (pressure reducer) with such a system beats me, but then maybe there's more to this plumbing system than I have in mind.

                        I do think Rick has it right that the regulator needs repair or replacement.

                        It sure would be nice if you had some special T fittings and a few pressure gauges. Then you could monitor and log readings. It would help us on the forum to get a better understanding.

                        We really would love pictures if you can sometime post them. Start where the water comes into your place and go from there around your basement.

                        The changes I had in mind need for me to try to either find pictures or draw up something. Maybe I can draw it good enough (not skilled in such) that you'll get the idea.

                        Question: Where do you have any pressure gauges for right now? If you have any that are installed, try opening the cold water valve just a crack in one sink with everything else off. Take a reading. The open it wide open and take another reading. Then close everything tight and watch the pressure gauge(s) for a few minutes. What happens? Be sure your water heater isn't heating during this test. If electric shut off power a few minutes before the test and if gas try setting the thermostat low. Remember to reset things later.

                        I bet Rick knows what I have in mind with this little test. He is the brains of this forum.

                        Comment


                        • #13
                          Re: Pressure Relief Valve

                          Woussko,
                          Well, I just read your post and went out and ran the tests you decribed. here are the results.

                          First let me say I do not have a basement and all the plumbing comes into a small room out in the garage. We are in the country, but the county water district furnishes our drinking water.

                          I placed my gauge on a hose bibb and the reading went to 96# and settled to 93#.

                          I cracked the sink faucet open just a little and it dropped to about 84#.

                          I opened the faucet up and it dropped to 45#.

                          By the way there are no gauges installed in the lines, next time the plumber is out I am going to get him to put one in past the pressure reducing valve at least. Now I am checking with a pump tank gauge that I have rigged up to fit on a hose bibb.

                          I closed it off again and it went back to the 92#-93# in about 30 seconds and seemed to hold in the 92#-93#area and stay there.
                          Anyway thanks for the response and I look forward to your thoughts on these results.-TPS

                          Comment


                          • #14
                            Re: Pressure Relief Valve

                            I think Rick nailed it that your pressure regulator needs to be replaced. For safety reasons it would be wise to install a relief valve set about 75 PSI just after the regulator and drain it into a floor drain out outside. You might get with your local county water company and ask if they have a pressure regulator near you outside. If yes, it needs to be repaired or replaced. When all is done you want to aim at 40 - 50 PSI water pressure throughout your home.

                            As to what's going on it sure seems like the regulator is leaking. If it closed off tight and was set at say 50 PSI you should hold much closer to that.

                            Comment


                            • #15
                              Re: Pressure Relief Valve

                              Just want to thank you all for the help!! Got my PRV in and got it on with no leaks. Should be a lot easier to change in the future with the double U joints. Set the pressure at 55psi and so far all is good. I was a little worried because the double U took a little more space to get it in and luckily the line to it was long and had some play so I was able to move it out enough to get it back in and it lined up and snugged up fine.
                              Thanks again to all who helped on this fine site. I am grateful-TPS

                              Comment

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