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  • #16
    Re: Thermal Expansion Bypass

    Originally posted by DUNBAR View Post
    Not to piss in your wheaties so early in the morning, but I disagree, heavily with this statement. Correct me if my logic goes astray.



    Every single valve, faucet, supply line, angle stop, fill valve, water heater, dishwasher, icemaker, washing machine that accepts water and water pressure to operate,

    is designed and engineered to 60psi. We all know it can operate at higher pressures, but all the flow restrictors on aerators, solenoid valves on dishwashers/ice makers/humidifiers on furnaces/washing machines work off timed solenoid valves, not metered water calculations. The water calculations are visioned at 60psi @ so many minutes to figure a gallon requirement.

    dunbar, slow down. the only valve that fills on a timed only cycle is the one on an ice maker. dishwasher has a float, washing machine has a pressure diaphragm that adjust for the size load you set. don't know about humidifiers. an ice maker does have an adjustment for a water pressure. yes there are timers, but that's just for the cycle. the water is still regulated by the floats or diaphragm/ pressure switch.

    remember that thermal expansion is present in 100% of all hot water heating systems. every pressure regulator has an opening and closing range. the 90# max. spike is not a super serious rise above normal operating pressure. remember that this is not going to stay 90# as soon as any fixture is opened. what is important is there a check valve or back-flow devise in the system.

    we are required to have expansion tanks when there are check valves and back flow devises. also if the city pressure is near or above the relief valve pressure. typically 150#. typically every prv has a thermal bypass. this allows for excess pressure to go back into the city main. don't know where you got that 135# figure from, but it's not on the wilkins or honeywell regulators i install. a regulator will allow for backflow. every shut off a home and open a hose bibb before the regulator. didn't you ever see the hose bibb surge as the pressure dropped and it emptied the house water.

    sure an expansion tank will help absorb the thermal expansion, but is not a requirement unless certain other factors are present.

    i am willing to bet that less than 5% of my customers have an expansion tank and i'm willing to say that other local plumbers out here have similar numbers. the ones that do is because they have circ pumps with a check valve on the system.

    our residential water meters don't have back flow preventers.



    IF, you take your water pressure above 60, all those gpm flow restrictors are now inaccurate, they are higher than what the flow rates indicate.


    As far as water wasted with high water pressure?


    If a washing machine is engineered for 60psi and you're running 90, you're diluting the cycles which equates to wasted water over a 3-5 time fill up for each time the device demands water.

    once again the pressure spike is just a momentary instance. water is not compressible, it's a hydraulic. squeeze an extra ounce of water into a tank and watch the pressure spike. air on the other hand is compressible.


    Furthermore, in relation to toilets, when a fill valve is engineered for 60 psi and the fill tube into the overflow satisfies the requirement of replenishing the water in the bowl for the next flush, any water after that point is now draining over the traps weir and wasting water at this point. Higher water pressure, more waste.

    higher water pressure would equate to a louder and faster fill. therefore the toilet will shut off faster than before. the refill and main fill are designed as a percentage of each. a tank toilet requires a min. of 15#. a toilet ballcock is not set just to 1 exact pressure.


    Same goes for dishwashers. When you wash your hands, you don't care if it's 100 pounds or 50; you just want your hands clean.

    remember thermal expansion pressure spikes last until the first fixture is opened. not the entire time your running water.


    The cyclical methods of everyday use of plumbing can create a substantial gallon overage quite quickly. The analogy I use heavily is to tell a customer if you like high water pressure so much,

    how about you go and buy every gallon of water you just wasted at the grocery store, every day. That's an eye opener to all of them. It adds up folks, real quick.


    Here's two others I use to solidify the need for protection, regulating your water pressure to "Normal" pressures that correlate to manufacture designs,


    Do you go to the doctor, doctor tells you that you have high blood pressure, and you refuse to take it?

    Do you take your vehicle to the garage and tell the mechanic to put 10-20-40 more pounds of pressure into the tires?

    Of course not.

    It all follows the premace of logical thinking, cause and effect of plumbing systems and how they operate both in normal fashion and in the altered state when devices are subjected to pressures higher than what they were designed for.


    I wrote all this out because anyone can take this knowledge and run with it. It is what I say over and over and over to my customers when I walk into their home, check the water pressure and it's elevated.

    However, I don't push the protection until it gets above 75. I'll notate anything over 60 as high, but I would not commit a customer to a PRV/EXP tank at 65, 70. 10 pounds is minimal and I wouldn't want a second opinion coming after me in a known area where water pressure stayed below 80 pounds.


    As plumbers in this profession, (I'm preaching at this point )

    IF you knowingly walk into a home and touch anything that has a water line connected to it, the first thing you should of done when you arrived is CHECK THE WATER PRESSURE. Doesn't matter if you've worked in the area for years; each one can have a different set of circumstances and you need it from a liability perspective on all counts. If you touch a faucet, supply line or valve and it blows off, ruptures or what have you, It's still your fault and a liability claim but you need to know why.

    Having that pressure gauge in your hands is the same as a doctor when they see you. What's the first two things they do? Check your blood pressure, then your temperature. They want to check for symptoms that lead to underlining problems. That is what we as plumbers are trained to do...not just fix the symptoms and move on.


    I couldn't tell you how many thousands I've made off of these issues in my area, but I'll tell you that every customer that committed to this protection, it might of knocked me out of a job in the long run in regards to product failure, but I feel good knowing I've done something on the level that protects the consumer from constant money spending, instead of the plumber knowingly ignoring the core issue that's keeping him/her gainfully employed.

    Codes across the United States embed the code or regulation for protection over 80 pounds. This is further indication that elevated pressure do cause problems in plumbing systems.
    80# is the code here too. but that is static pressure, not thermal expansion pressure. remember that pressure relief valves are set to 125-150# for a reason. if every time a water heater were to fire and the relief valve were to open, then you'd have an issue.

    thermal expansion affects every hot water system. maintaining a safe system is what regulators, and relief valves are designed for. 90# spike due to thermal expansion is not out of the ordinary. it's a temporary increase that will go away as soon as any fixture is opened.

    by the way, i have 4 expansion tanks in stock. i might sell 1 a year.

    rick.
    phoebe it is

    Comment


    • #17
      Re: Thermal Expansion Bypass

      Rick I agree with almost everything you said except the part about the check valve on the recirc system. A washing machine might surge for a moment when it is first turned on but I have seen Fluid Master fill valves operate the same under high and low water pressure situations. Remember that thermal expansion starts on the hot side and pushes into the cold side of a house system unless there is a check valve present on the cold side at the water heater.

      Comment


      • #18
        Re: Thermal Expansion Bypass

        Hi everyone,
        Wow a lot of responses! I can't find a place to check the pressure before the PRV. I looked outside by the water meter, don't see anything where I can directly check the street pressure. Sooo maybe I'll leave the water pressure gauge on all night and see what the spike is for a longer period of time.

        There is not a lot of room to install an expansion tank -- I'll try to attach a pic at some point.

        Someone told me a PRV should not let the pressure go above 10 above the street pressure during thermal expansion. Since I was "told" by the water company the street pressure was 80 (who knows right), I'm guessing 90 is normal ish (Rick, you're right, it's not 90 for a long time. People always using the bathroom.).

        I also can't tell whether we've come to a conclusion that I don't need a tank or not?

        Comment


        • #19
          Re: Thermal Expansion Bypass

          Originally posted by natalie1999 View Post
          Hi everyone,
          Wow a lot of responses! I can't find a place to check the pressure before the PRV. I looked outside by the water meter, don't see anything where I can directly check the street pressure. Sooo maybe I'll leave the water pressure gauge on all night and see what the spike is for a longer period of time.

          There is not a lot of room to install an expansion tank -- I'll try to attach a pic at some point.

          Someone told me a PRV should not let the pressure go above 10 above the street pressure during thermal expansion. Since I was "told" by the water company the street pressure was 80 (who knows right), I'm guessing 90 is normal ish (Rick, you're right, it's not 90 for a long time. People always using the bathroom.).

          I also can't tell whether we've come to a conclusion that I don't need a tank or not?
          Your water purveyor should be able to give you that information over the phone. Ask them for the minimum and maximum supply pressures. Depending on where your source is it could vary quite a bit through the year. I had one the other day which had a minimum of 107 and a high of 151. Under our Code (UPC) the expansion tank was required because the supply pressure exceeded 150 psi (relief pressure at T&P).

          Mark
          "Somewhere a Village is Missing Twelve Idiots!" - Casey Anthony

          I never lost a cent on the jobs I didn't get!

          Comment


          • #20
            Re: Thermal Expansion Bypass

            Hi,
            Yeah I called our water authority a week ago and the lady said the pressure was 80. I'm not sure if she really knew anything besides what the higher ups were telling her. Should I ask for them to come out and read the pressure or ask for something more specific?

            I just took a shower, went downstairs and watched the pressure gauge. As the water heater was running, I watched the pressure increase to 105 psi. No one was using water at this time. The heater shut off and the pressure started to go down by itself. Went down to 67 psi and then stopped. I got tired of watching and came back upstairs. Used a bit of water to clean the bathtub and checked again. The pressure was back to 47 psi (our regulated pressure).

            Should I just install an expansion tank? This is how our water system has been running for 8 years but I rather be safe than sorry.

            Comment


            • #21
              Re: Thermal Expansion Bypass

              Yes, put the expansion tank in.

              You've answered your own question by stating you'd rather be safe than sorry.

              J.C.

              Comment


              • #22
                Re: Thermal Expansion Bypass

                Originally posted by ToUtahNow View Post
                By the way just as an FYI all faucets, valves and fittings are regulated by ASME A112.18.1 which requires they be designed to operate at pressures between 20 psi and 125 psi. I believe a more accurate statement would be the optimal pressure for operation is 60 psi.

                Mark


                Yes,


                60 psi is what all flow restrictors are based on to arrive at GPM ratings.


                Calculations are derived from this 60psi.
                Northern Kentucky Plumbers Twitter Feed | Plumbing Videos

                Comment


                • #23
                  Re: Thermal Expansion Bypass

                  Originally posted by PLUMBER RICK View Post
                  dunbar, slow down. the only valve that fills on a timed only cycle is the one on an ice maker. dishwasher has a float, washing machine has a pressure diaphragm that adjust for the size load you set. don't know about humidifiers. an ice maker does have an adjustment for a water pressure. yes there are timers, but that's just for the cycle. the water is still regulated by the floats or diaphragm/ pressure switch. I'd like you to show me exactly what operates a dishwasher, and a washing machine. Kick on, run for XX amount of seconds, kick off. Hard slam of a solenoid valve. We all know what hard slamming and high water pressure does in regards to sending shock waves through the piping inside a plumbing system.

                  remember that thermal expansion is present in 100% of all hot water heating systems. every pressure regulator has an opening and closing range. the 90# max. spike is not a super serious rise above normal operating pressure. remember that this is not going to stay 90# as soon as any fixture is opened. what is important is there a check valve or back-flow devise in the system.
                  ????? I'm speaking of potable water systems, not hot water heating systems

                  we are required to have expansion tanks when there are check valves and back flow devises. also if the city pressure is near or above the relief valve pressure. typically 150#. Are you telling me that someon would consider 140psi "safe" in your neck of the woods?

                  typically every prv has a thermal bypass. this allows for excess pressure to go back into the city main. don't know where you got that 135# figure from, First and foremost, I wouldn't put a Wilkins PRV in a dog house, they're junk, short life and that's why they're the cheapest. Second, Watts puts it out there 135 is where the bypass opens, only if the main line pressure isn't matching or above. IOW, it's useless in the big picture of thermal expansion and the problems it creates.

                  but it's not on the wilkins or honeywell regulators i install. a regulator will allow for backflow. every shut off a home and open a hose bibb before the regulator. didn't you ever see the hose bibb surge as the pressure dropped and it emptied the house water. Yes. At some point it will release, but only at zero pressure on the line, not static and running.

                  sure an expansion tank will help absorb the thermal expansion, but is not a requirement unless certain other factors are present. Do you know how pointless a PRV is when you install one, then a water heater @ 120 degrees fires and creates a ready to use cycle of hot water over a 3-5 hour period? Do you know the pressure amount @ 130 degrees?




                  i am willing to bet that less than 5% of my customers have an expansion tank and i'm willing to say that other local plumbers out here have similar numbers. the ones that do is because they have circ pumps with a check valve on the system. Thermal expansion is found everywhere in potable water systems. I've seen too many threads in too many forums where a customer will have a PRV set @ 45-60 pounds and they start having problems when they start spiking to 90, and you're calling this, "okay?"

                  Why put the damn PRV on to begin with when you're going to recreate static pressure higher than the setting of the PRV?


                  our residential water meters don't have back flow preventers. That's a practice that's a great one, it's built right into the meter bracket, and that means mandatory expansion tank or some type of thermal expansion device. Once the Water Purveyor delivers water to a structure, they never want it back; that school of thinking protects the masses from cross connections that can reenter into the public water supply.





                  once again the pressure spike is just a momentary instance. water is not compressible, it's a hydraulic. squeeze an extra ounce of water into a tank and watch the pressure spike. air on the other hand is compressible. Momentary?

                  Explain this one when a property owner with a PRV, no expansion tank takes a shower before going to bed and the heater runs to resupply demand for the morning shower or use.

                  Thermal Expansion in a closed system has absolutely no where to go. Only UNTIL someone gets up, flushes a toilet, runs a sink or runs ANY water in that system is when that additional pressure is going to release. Until then, that pressure will continue to climb unless there is the weakest link in the chain that's relieving itself, indicator lights that's something is wrong.







                  higher water pressure would equate to a louder and faster fill. therefore the toilet will shut off faster than before. the refill and main fill are designed as a percentage of each. a tank toilet requires a min. of 15#. a toilet ballcock is not set just to 1 exact pressure.


                  Set up two toilets, one at one pressure and one at 90 pounds and tell me how much water enters the drain of that water closet by method of the fil tube for the overflow.

                  Do you know how many fill valves get replaced as a result of high water pressure?



                  remember thermal expansion pressure spikes last until the first fixture is opened. not the entire time your running water. ????


                  80# is the code here too. but that is static pressure, not thermal expansion pressure. remember that pressure relief valves are set to 125-150# for a reason. if every time a water heater were to fire and the relief valve were to open, then you'd have an issue. Do you gauge every job you go to when you replace a faucet, a valve, a water heater?

                  It's commonly known that BEFORE you gauge static water pressure, you must run that faucet or fixture to remove all thermal expansion buildup to get an accurate reading of the main line and what's feeding the structure.

                  Pressure Relief Valves are set to 150psi/210 degree blowoff. It's a safety valve, it's not a device to address thermal expansion as you're stating it.

                  thermal expansion affects every hot water system. maintaining a safe system is what regulators, and relief valves are designed for. 90# spike due to thermal expansion is not out of the ordinary. it's a temporary increase that will go away as soon as any fixture is opened. Thinking like this is detrimental to your customer base, especially if you're installing PRV's without any thermal expansion protection. You're "recreating" high pressure within the plumbing system which is incorrect on all counts.


                  by the way, i have 4 expansion tanks in stock. i might sell 1 a year.

                  rick.

                  If you're selling one a year, you're definitely doing yourself no favors in protecting the public from high water pressure. If you're stating for the forum board that "90" is no big deal, it's temporary, then you certainly don't think statewide code of "80" is no big deal either.

                  Job today,

                  Expansion tank pinholing right at the weld of the MIP...I told the guy his water pressure was high last time I was there, I check it today, 120+ pounds.

                  I replaced the EXP tank and installed a PRV, set it to 60 on both. WHY?

                  Because the tank mfg. of almost all of them state to NOT set the bladder pressure no higher than 85psi,

                  Explain why the majority of all PRV's have a 25-75 range if there's a happy middle ground between those two numbers that follows most recommendations of water pressure

                  Explain why the presets of thermal expansion tanks of 40psi


                  Explain why those thermal expansion ball valves are designed to open at 75-80

                  Explain why private water systems have a common 75 pressure relief valve

                  Explain why I make thousands of dollars inside homes when the water pressure is 80 and above, but when I install a PRV and EXP tank, the repairs significantly stop, and the plumbing system operates without error or malfunction in such a different way than someone who has 80 pounds of pressure.


                  I've seen way too much property damage, leaks, breaks, ruptures, exploding supply lines when the pressure goes above 80, and I believe that I'd trust the logic of the state to state codes that 80 and above requires some type of protection,

                  whether it works in LA or not.

                  A thermal expansion tank can adjust to a 1/2 pound of thermal expansion, no other device in plumbing offers that protection for the cost and design.
                  Last edited by DUNBAR PLUMBING; 02-16-2009, 10:57 PM.
                  Northern Kentucky Plumbers Twitter Feed | Plumbing Videos

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                  • #24
                    Re: Thermal Expansion Bypass

                    Thanks for everyone's help on this. I've basically decided to put in an expansion tank. Past 100 psi seems dangerous even if it is temporary.

                    I attach pics here. Do you think there's enough room to put it on the cold side (which I'm guessing is the right side, where the shut off valve is). Would it need some kind of support? I think there is room, although it will be tight.

                    There are two pictures to show as complete a picture of the area as I could manage.
                    Attached Files

                    Comment


                    • #25
                      Re: Thermal Expansion Bypass

                      Yes, a plumber can handle an expansion tank in there easily enough. Have them check the vent on the water heater also.

                      J.C.

                      Comment


                      • #26
                        Re: Thermal Expansion Bypass

                        dunbar, quoting the code addresses the need for an expansion tank.

                        out of the 5 different cities i work in, not 1 of them utilize any check valves in their meters. water is free to go back into the city main.

                        unless there is a check valve/ back flow preventer or the city has a high approaching 150# an expansion tank is not required by code.

                        don't know if you have any experience in high rise plumbing or construction. but it's not uncommon to run at pressures above 80#.
                        the pressure zones vary based on the floor level above or below the regulator stations.

                        maintaining an exact 60# in a system is both unnecessary and unfeasible. an expansion tank will actually create a scenario of constantly compressing and expanding the bladder. a regulator has a drop off based on demand.

                        the regulators that i install all incorporate a thermal expansion bypass.

                        i can tell you from real life experience and the thousands of customers i have and customers that i cover for. less than 2% of them have an expansion tank. probably closer to 1%.

                        this also includes the thousands of units i worked on in 15 years of new construction.

                        we are not on private wells. we are on city mains.

                        by the way, dishwashers, washing machines, ice makers all incorporate an electric solenoid valve, but they are controlled by a float, pressure switch or timed cycle. and yes they will shut off fast. an expansion tank will help absorb the shock, but so will a hammer arrestor or an air chamber.

                        the pressure gauge i use to measure pressure is a certified instrument glycerin filled gauge. runs almost $300. so yes i do check pressures. i replace regulators since rebuilding them is usually not cost affective.

                        but installing an expansion tank in every installation is not what any of us do out here. if it was, then all my supply houses would be stocking them by the hundreds, not by the 1/2 dozen.

                        rick.
                        phoebe it is

                        Comment


                        • #27
                          Re: Thermal Expansion Bypass

                          Can anyone tell me which regulators are currently being sold that do not have a thermal bypass?How about the olde,any popular ones that I can warn my customers about?

                          Comment


                          • #28
                            Re: Thermal Expansion Bypass

                            Originally posted by rookie plumber View Post
                            Go buy a water pressure test gauge and tell us what your pressure is before the regulator. How old is your regulator and what size is it?
                            Thanks for this picture, made My week! Send it into the papers,It's Great,and what a handsome PLUMBER! Tool
                            I can build anything You want , if you draw a picture of it , on the back of a big enough check .

                            Comment


                            • #29
                              Re: Thermal Expansion Bypass

                              Originally posted by natalie1999 View Post
                              Thanks for everyone's help on this. I've basically decided to put in an expansion tank. Past 100 psi seems dangerous even if it is temporary.

                              I attach pics here. Do you think there's enough room to put it on the cold side (which I'm guessing is the right side, where the shut off valve is). Would it need some kind of support? I think there is room, although it will be tight.

                              There are two pictures to show as complete a picture of the area as I could manage.
                              Your plumbing will last longer for it!
                              You might want to replace (with hard) or support that flue vent from the water heater. The flex pipe can sag over time and cause flow issues.

                              Comment


                              • #30
                                Re: Thermal Expansion Bypass

                                Thanks -- I'm trying to get some estimates from reputable plumbers in my area.

                                From the picture I posted, how hard of a job would it be to replace our water pressure regulator? It is a Watts N35B, which I couldn't find on the watts website (it seems they have N45B now). A couple of days ago, I asked a plumber how much to replace this and he said $457. The part is only 80-100 dollars. He said to also replace the main water valve because it was cheap and he recommended replacing it with the kind that is a lever ($200 to do that). I thought this was over the top expensive because he admitted the parts would cost no more than 120 for both regulator and valve.

                                Thoughts? I have a good handyman so if it's not too complicated, I was going to ask him to do it. He's fixed angle valves, supply lines, and my toilets.

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