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Need help with water service noise / banging....

Timco
Timco Member Posts: 3,040
So my old setup was just pipe, an old valve, and iron pipe into the water heater, 40 gal. No checks, xtank or anything. Never a problem.



New system is all copper, tankless, x tank, PRV, and filter on service with gauges before & after PRV. At night, I noticed constant banging throughout the house. Few days later, I realize it's all day, and it's the water service. Gauges show pressure coming in at 78, house set to 65. Incoming pressure varies a few lbs, then dropped to 65 or less, and when it recharged it banged my pipes hard. This happened over and over. So I call the City. We watch the meter as it "breaths" in & out against my x tank. No check on the meter or yolk.



So I install a swing check first thing in line inside my house. Now, I can hear the banging of the service drop and recharge, but my gauges stay firm. Much, much quieter (faint) but rhythmic and constant. Thump, thump, thumpthumpthump, thump.



My concern is how this affects my 100+ year old service line. Now I see more & more rust in the house filter.



Can I demand a check at the meter??
Just a guy running some pipes.

Comments

  • Gordy
    Gordy Member Posts: 9,546
    Who Is Responible

    For the service line to the meter?



    Around here if they do a total Recon on the street all services are replaced to the home at cities expense. If there is a failure homeowner is responsible to the shut off at the street.



    Interesting problem. Yes I would be worried about my service. Sounds like its getting banged pretty good. IS it Iron, Lead? I assume iron from the rust in the filter you observe, but may e coming from farther upstream?
  • kevin_58
    kevin_58 Member Posts: 61
    banging pipes

    Is noise constant or only when running water?  I saw a few jobs that banged when water was running, In those cases it was the reducing valve, it would reduce then not then reduce over and over causing the pipes to bang.
  • Weezbo
    Weezbo Member Posts: 6,232
    double check

    we are required to use lead free double checks after the regulator after the meter .

    Banging from pressure surges on city side does not sound like harvey homeowner problem.
  • Jamie Hall
    Jamie Hall Member Posts: 23,090
    A few thoughts

    Well, really just one.  What appears to be happening is that the pressure reducing valve (which acts like kind of check on reverse flow) or the swing check you installed are closing and opening abruptly, creating the water hammer.  It should stop if you are running no water at all; it should also stop if you run enough water to drop the pressure through the valves to below the pressure reducing valve setting,



    If it's doing it all the time, you might want to check and be sure you have no leaks or drips in your inside plumbing,



    This kind of thing can be very very difficult to cure, however.  The first thing I would be inclined to look at is just how close the expansion tank is to the PRV.  The closer it is -- preferably immediately after, with as close a connection as possible to the main -- the better it will be; if there is any significant amount of pipe between the two, this kind of thing can happen (it can also happen on deep well pumps).  The second thing to check is to make sure that that expansion tank is big enough (it would be hard to have it too big!) and that it is in fact precharged to your PRV's set pressure.



    You may have to do considerable fiddling to cure this.



    A rather obvious question, though -- 78 psi street pressure isn't out of line.  Why do you feel a need to reduce it at all?



    The constant or near constant hammering is definitely not good, and you should try and fix it as soon as you can,
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • Timco
    Timco Member Posts: 3,040
    responsibility

    Here it's the City up to the meter, then me.



    It's an iron pipe, 3/4". 1910.



    Filter has gotten pretty orange in the past couple days. Seems to be getting worse.
    Just a guy running some pipes.
  • Timco
    Timco Member Posts: 3,040
    running?

    It's constant. Only happens when I am not running water. It can clearly be heard if you're down by the water entry.
    Just a guy running some pipes.
  • Timco
    Timco Member Posts: 3,040
    check valve

    It's not my check valve because that's what keeps my gauges solid and stopped the banging from echoing through my house. Now it's in the main only. It only happens when the water ism not running. I installed a PRV to make it all new and code. It's cranked in as far as it will go. City pressure drops below my setting of 68lbs and my check holds it there, but it now thumps back up to pressure against my charged, closed system.



    Tank is the big tank, but it's about 30' away from the entry where the tankless / boiler combo hangs. Pics in a minute. It's charged to 68-70lbs.



    No leaks in my plumbing. This is city pressure banging against my system as it recharges. Pressure fluctuated at the hydrant, then dropped and rose, but he said that was normal.
    Just a guy running some pipes.
  • Timco
    Timco Member Posts: 3,040
    pics

    A few pics
    Just a guy running some pipes.
  • kevin_58
    kevin_58 Member Posts: 61
    banging pipes

    If incoming water pressure is only 78 lbs why not loose the prv. I dont know your codes but maybe loose check valve and expantion tank, it sounds like thats the way you were before the work done.
  • Weezbo
    Weezbo Member Posts: 6,232
    edited October 2013
    anti-backflow suppression valve

    i see a back flow preventor on the feed water system guys so it is not like the boilers got anything to do with the surges,

    there is a strainer on tthe aub 25 which i have seen sediments the size of rocks foul up after taking the entire diaphram out to see what was what with it ...

    we flush the lines from the city and we have both a supply and return latteral so our "Main is essentialy within the home inches away from the lead free aub, water meter and lead free double check . our llatterals are usually copper . many years ago we had some single pipe almost all have been eliminated from the muni.
  • Jamie Hall
    Jamie Hall Member Posts: 23,090
    Upon further thought

    and your further notes, you are also going to need an expansion tank on the service side of your check valve/PRV arrangement.  This should be precharged, of course, to the street service pressure.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • Larry Weingarten
    Larry Weingarten Member Posts: 3,268
    if the pressure fluctuations...

    ... are caused by the water supplier, then they are likely having a pumping problem and need to know about it.  I had a problem where the house pressure fell to less than zero every 55 minutes, but only for a second.  The nearby pumping station controls were messed up and the water utility didn't know.  A recording pressure gauge might be useful. 



    Yours,  Larry
  • Timco
    Timco Member Posts: 3,040
    Gravity

    We are gravity here. I am one block below a reducing valve. A block east the pressure is 120 coming into my 4-plex. There is a hospital across the street from me. City has been out and confirmed I don't have a check at the meter.



    Also, now faucets shut off fast or the dish washer will make my pipes bang now.



    Sheeeeeeeeeesh!!!!!!!!
    Just a guy running some pipes.
  • Timco
    Timco Member Posts: 3,040
    Drum solo!

    Finally spent time down there tiling the shower.



    Water service sounds like a drum solo during the day! Here's the kicker. I tried something totally radical and turned off the ball valve servicing my house. Silence. Total silence.



    Then turn BV on and badda da badda da badda de thump.



    Idea of pull tank and check seems best?
    Just a guy running some pipes.
  • hot_rod
    hot_rod Member Posts: 21,975
    What about a water hammer

    Arrestor? We suggest them to cure back flow hammer and leaks. Sioux Chief makes a wide selection
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • kevin_58
    kevin_58 Member Posts: 61
    banging pipes

    I read your 1st post again and it seems like it all started after the prv and expantion tank was installed. I would remove them. and without expantion tank you have to get rid of the check valve to.
  • Jamie Hall
    Jamie Hall Member Posts: 23,090
    Well, yes

    that would be the easiest and simplest thing to do, and the street pressure isn't that high.  In suggesting an expansion tank/surge arrestor on the street side of everything, I was assuming that, for some reason, the OP wants the pressure dropped...
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • Timco
    Timco Member Posts: 3,040
    Under pressure

    Me no wants less pressure! Just wanted it to be an all new & code install but I've gotta dump that PRV and check and xtank.



    What if city looses their reg? And I'm not up to code or have no reg? Install the next larger and set to 80lbs? No check or xtank?
    Just a guy running some pipes.
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