Thermal Expansion

Discussion in 'Plumbing Forum, Professional & DIY Advice' started by gnrboyd, Feb 7, 2014.

  1. gnrboyd

    gnrboyd New Member

    Messages:
    21
    Location:
    Missouri
    I have a question regarding thermal expansion.....

    If you have thermal expansion going on in your water lines (no expansion tank), does it immediately dissipate when you turn on a water valve?

    I am having with vibration/growling noises coming from my pipes. (explained in great detail in another post that didn't get much attention) I can turn on a trickle to any faucet, and my pipes vibrate/growl. I can let it run at a trickle indefinitely and the noise never stops. I can turn on the water full and the vibration stops but immediately comes back when I turn the faucet back to a trickle. I would think that if thermal expansion was the culprit, the noise would take considerable time to come back after opening up the faucet for a while. Am I wrong?

    The PRV has been replaced twice in the last several months. The original one was a Watts N35B that went bad after 14 years. I replaced it with a Cash Acme EB-45 a few months ago and then with a Cash Acme EB-45DU a couple of weeks ago. Since the new valves were put in, I have experienced a wide variety of sounds ranging from high pitched tuning fork sounds, vibrations, growling, etc. Could 2 units be bad? Both are in working order regarding the pressure reduction.

    I am on the fence between bad PRV (or wrong type, bad quality) and thermal expansion being the cause of the noises.

    Oh... and by the way, the city water pressure is around 150 before the PRV in my house. The water dept. confirmed the pressure is high but normal for where I am located. (down in valley)

    Any help, thoughts or ideas would be appreciated.
  2. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    22,262
    Location:
    New England
    Thermal expansion only occurs while the WH is actually running (well, maybe a minute or two after from residual heat). Have you checked your pressure after the PRV? Does it stay stable? If you do not have an expansion tank, it WILL go up when the WH is running after using some hot water UNLESS, there's a leak somewhere in the house (a toilet fill valve is a common weak point). Maybe if you have all pex, that may absorb some of the expansion, along with the flexible supply hoses to the WM, or faucets, but that's not healthy for them over time.

    If the seal on the PRV isn't working well, you may hear some water pushing past it if it isn't working properly, or if the PRV has a bypass valve, but that can't open until the house pressure exceeds the supply, and the safety valve on the water heater is also designed to open at 150psi..

    So, the first thing I'd do is to check the water pressure. Pick up a gauge with a tattle tale hand that shows peak pressure and leave it hooked up for 24-hours. Keep in mind that the T&P safety valve on your water heater will vent if the expansion pressure gets to 150psi, and that can make some noises, too.

    The thermal expansion will dissipate within a few seconds from the flexible hoses in the house when you open a valve - normal copper pipe will not expand or flex to accommodate the relatively low pressure from the supply, but the hoses can, acting like a water balloon to release that pressure when you open a valve.

    Get yourself an expansion tank.

    Most PRVs can handle 150psi on the inlet, but some may not, and those may require you to step the pressure down with two of them in line.
  3. gnrboyd

    gnrboyd New Member

    Messages:
    21
    Location:
    Missouri
    jadnashua,

    Thanks for the reply.

    Yes, I have hooked up a gauge to my gas water heater drain valve. It reads 50 every time I look at it but the tattle needle shows that it has spiked to 75-80. I have done this a couple of different times for a 24 hour (or more) period and each time have had similar results.

    I have all copper lines. (3/4" & 1/2")

    I don't think there is any bypass on the PRV. With 150 incoming pressure, I don't think any water will ever push past the PRV anyway based upon the readings I have taken at the water tank.

    It doesn't make sense to me why I would need an expansion tank if I didn't have one for the first 15 years and never heard any of those sounds. I'm not saying it isn't a good idea, but I don't see how it can be causing the problems I have previously described. You said the thermal expansion only occurs when the heater is running or slightly after. I can let the faucet trickle for an endless amount of time and it makes the sound/vibration even though the water heater may not be running. Can you explain that? What am I missing?

    The two I replaced so far (Cash Acme EB-45 and EB-45DU) indicate they can handle 400 psi.

    To recap my situation....

    1. The noise is present for an endless amount of time so I don't see how thermal expansion could be the cause. I didn't have an expansion tank in the system since the house was built 15 years ago and did not hear these noises. My thinking is that while it may be a good idea to add one, I don't think thermal expansion is causing the noise I am hearing. (Please feel free to prove me wrong.)

    2. I installed 2 brand new PRVs and both have made noise. They are basically the same model but one is lead free. I don't see how both could be defective.

    3. I have turned off all of the valves in the house (washer, sinks, toilets, etc.) trying to isolate the noise to a fixture but it is still present when they are all off. I don't have a shut off to any of the 3 showers, but I replaced cartridges in 2 of them recently and the other one is never used. The noise/vibration is the strongest where the water comes in the house around the PRV. The sound and vibration can also be heard and felt at the meter in the front yard. (The water company even replaced the meter to see if that was the problem but didn't change anything.)

    I'm stumped.
  4. jm66208

    jm66208 Member

    Messages:
    99
    Location:
    KC
    The noise is a rubber washer somewhere flapping like the reed in a duck call as water passes over it. It's either the main (globe) valve, or the PRV.
    Last edited: Feb 8, 2014
  5. gnrboyd

    gnrboyd New Member

    Messages:
    21
    Location:
    Missouri
    jm66208... I replaced the washer yesterday in the main valve and it didn't help. (I replied with more details in my other post.)
  6. jim mills

    jim mills New Member

    Messages:
    141
    Location:
    nebraska
    Not trying to insult you, but are you sure you used the correct washer? Did you put it on backwards? Did you have the stem backed out all the way when you tightened the packing nut? Make sure...
    Also, might change that CA PRV out for a watts u5B from a supply house. I hate to recommend parts or brands anymore, because quality is getting so bad, but I wouldn't get one from the big box store for sure.
    Last edited: Feb 8, 2014
  7. gnrboyd

    gnrboyd New Member

    Messages:
    21
    Location:
    Missouri
    Feel free to insult me any time. :D I fully admit that I am no plumber for sure! The washer that was in the faucet was a black rubber and flat. I found that the 1/2" washer at the hardware store was the same size and was a tight fit inside the cup on the end of the stem. Since it was flat, I didn't think it had to go one way or the other. I don't know for sure if I had the stem all the way out or not. Maybe that was the problem?

    I have the water turned off now so I thought of another possible cause. Right after the main shut off, the pipe goes vertical for a short distance and then has a T fitting (3/4 on one side, 1/2 on the other) On the 3/4 side, it goes to the PRV. The 1/2 side goes to a shut off valve (like hose bib) about a foot away. (This is in my sub-basement and I never use this valve nor could I ever figure out why it was installed this way when the house was built.) On the end of the valve, there is a brass piece screwed on that has a set screw that has been broken off. I was able to use a pair of wire cutters to slowly back out the screw and then unscrew the fitting. When I looked at it, I noticed it had a spring in it. After a little research, I discovered that this is an anti-siphon device. I initially took the valve apart to just clean it out and check the condition of the washer. Now, I am wondering if it could be that this part is causing my problem. It really shouldn't as it isn't getting any water going through it. I am going to the hardware store to get a washer for this valve and then hook everything back up and see what happens with this piece off the end of the valve. I will post back later today with my results.

    If this isn't it, I may have to try a better quality PRV as you suggested. Thanks again for your feedback and suggestions.
    Last edited: Feb 8, 2014
  8. gnrboyd

    gnrboyd New Member

    Messages:
    21
    Location:
    Missouri
    I put everything back together and still have the noise. It isn't as bad at the moment, but if I play with the PRV settings I can make it come and go. Anything over 45-50 and it is worse than it was before. I have it set now somewhere around 45-50 and it only consistently makes the noise when the ice maker runs. I have a feeling that this will be short-lived and the noise will come back with the trickle.
  9. Reach4

    Reach4 Well-Known Member

    Messages:
    2,624
    Location:
    IL
    Could that extra pipe be used to drain the plumbing?
  10. jm66208

    jm66208 Member

    Messages:
    99
    Location:
    KC
    I doubt that device is causing the problem, but you can always just close the valve to see if that makes a difference.


    PS.its the prv...
  11. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    22,262
    Location:
    New England
    Shut the water off to your toilets temporarily, and then leave the water pressure gauge on overnight after having used some hot water. Toilet fill valves are a common source of noises if the pressure is higher than they like. On those, sometimes all it takes is a new seal, depends on the brand and model.

    75psi isn't all that high, but is higher than needed or available many places.
  12. gnrboyd

    gnrboyd New Member

    Messages:
    21
    Location:
    Missouri
    Yes, it can but the main valve itself has one of those small drain outlets with a brass cap on it which is a couple of feet lower than the extra line. I just used that when I drained it after opening up a couple of other faucets to get the bulk of it. You are probably right though, for the reason it was installed. This is a sub basement with a sump pump in it. Maybe they thought it might be useful to have a garden hose hooked up in that area.
  13. gnrboyd

    gnrboyd New Member

    Messages:
    21
    Location:
    Missouri
    I have previously shut off ALL of the small valves around toilets, sinks, refrigerator, dishwasher, etc. and the noise was still present. This ruled out the toilets or other fill valves since no water was getting to them. I guess it could be from any one of the 15 or more valves I have around the house that lead to those fixtures. If that was the case, wouldn't the noise be in that area and not down in the basement around the PRV?

    I replaced a washer in the extra valve near the PRV today and while the water was off, I took out the main valve apart again and also the PRV to look for gunk that may have been floating around. I didn't find anything.

    When I put it back together, at first it make all kinds of loud sounds that were worse than before. I played a little with the PRV valve and now most of the noise is gone that I was hearing earlier. I still hear it when I use the water dispenser on the refrigerator but I can't reproduce the sound when any faucet is at a trickle like before. I can play with the PRV pressure just a little and get it to start up again. Right now, I have it dialed in at 50 psi and most of the sound is gone so I am going to leave it alone for now. It seems very temperamental and I don't think it should be which makes be believe that the noise will come back. (Probably sooner than later.)
  14. gnrboyd

    gnrboyd New Member

    Messages:
    21
    Location:
    Missouri
    Just as I suspected, I am now able to once again get the vibration/jackhammer noise while running any faucet at a trickle.
  15. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    22,262
    Location:
    New England
    It may have been asked before, but what do you have for your main water shutoff valve?
  16. gnrboyd

    gnrboyd New Member

    Messages:
    21
    Location:
    Missouri
    I guess the correct term is globe valve. It has a 3/4 inlet with what I believe to be a union with flared fitting. The outlet is at 90 degrees with female threads going to a 3/4 copper male.

    I am getting away from the noise/vibration problem, but when I had it apart yesterday, I noticed that some of the threads on the male piece holding in the stem were starting to deteriorate and flake off. I don't know if I over-tightened it in the past while trying to stop a tiny leak or if perhaps it got cross threaded. The female threads seemed ok the best I could tell. If I have to take it apart again, I won't put it back in that condition as it will likely be even worse when I pull it out the next time. I emailed the company yesterday to see if parts for the valve were available. (Arrowhead) I would just replace the whole valve but I am concerned that the outlet side may be very difficult to get free and I could do more damage with my luck at home repairs. I would like to replace it with a ball valve but I might have to make more modifications than I would like. I am nearing the point of just calling a plumber to figure out this noise problem and just replace the valve at the same time. I don't think I have ever spent so much time on a problem with no progress in my life.

    Plumbing 006.jpg
    Last edited: Feb 9, 2014
  17. jm66208

    jm66208 Member

    Messages:
    99
    Location:
    KC
    While you would be doing no harm replacing that valve, it aint gonna fix the problem. Can you sweat solder? If you did that male thread adapter joint, I would say no...sorry. A short section of 3/4" copper, a 90 deg. elbow, a ball valve, and a coupler, and you could replace that valve. Only concern would be sweating the ball valve. It takes a better torch to sweat the ball valve quickly without cooking it, but it can be done.
    bv.jpg
    Last edited: Feb 9, 2014
  18. gnrboyd

    gnrboyd New Member

    Messages:
    21
    Location:
    Missouri
    I can and have sweat solder. I don't feel very comfortable doing it and it isn't all that pretty when I get done. I did not do the one in the photo but I do agree, it is ugly. the vertical pipe I connect to is about 8" from the wall so I don't have much room to play with to get that ball valve in. I just thought if I could replace the guts of my existing pipe to relieve my concerns about the crumbling threads it might be a good idea. I would probably be better to just replace the entire valve though. Do you think that joint with the male adapter would be hard to break? It looks pretty corroded. If I could break it free, and replace it with the same brand or something that I could re-use the existing flare fitting, I would give it a try.

    Yea, I agree... it isn't going to solve my noise/vibration/jack-hammer problem. That one is eating away at my life expectancy.

    By the way, I appreciate the time you took to draw up the diagram and try to help with other comments.
  19. Reach4

    Reach4 Well-Known Member

    Messages:
    2,624
    Location:
    IL
    Apollo 69BV series has essentially a union on each end. Each end can be one of 9 types of fitting including sweat. You can mix an match types but not sizes. 1/2, 3/4, and 1 inch only. Because the soldering can be done with the valve and O-ring detached, it does not require as much heat, to solder.

    http://www.apollovalves.com/products/by_product_specific/150
  20. gnrboyd

    gnrboyd New Member

    Messages:
    21
    Location:
    Missouri
    Ok.. let's take this a different direction.

    What do you think it should cost if I hired a plumber to do the following:

    1. Diagnose my noise/vibration problem. (I realize the cost for repairs would vary depending upon the diagnosis.)

    2. Replace main shut off valve as discussed previously in this post. (I am ok with the same type as I don't plan to be in this house more than 5 more years.)

    Possible other projects to bundle with 1 & 2.

    3. Replace my PRV with a better quality model which may require a pipe to be cut and a new male adapter soldered on. (Current model is Cash Acme EB-45DU)

    4. Solder on a 1/2 male adapter on a stub for the a tub spout diverter (different project). The 1/2 pipe has been crimped too hard by one of those set screw type tub spouts and I can't get it to seal. I'd like to have just a threaded end that I can screw a tub spout on and off without that silly set screw. I am too chicken to try it myself since it is 3"-4" from the tub wall.

    5. Add in a thermal expansion tank.

    6. Add in a hammer arrester somewhere in my system possibly around the water tank.

    (By the way, my house is all copper (3/4 & down) with the exception of the hoses on toilets, washing machine , water tank, etc.)

    I am sorry for this post bouncing around so much. I'm just weakening to the point of considering calling a plumber for help. I realize without seeing my house, the cost of the jobs may be difficult to determine but I am only looking for ball park amounts to help me figure out if I should call a pro or not.
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