HELP: Sprinkler RPZ valve and test cock port issue

Discussion in 'Plumbing Forum, Professional & DIY Advice, Tips & ' started by Chrstine, Jul 27, 2013.

  1. Chrstine

    Chrstine New Member

    Messages:
    4
    Location:
    NJ
    Hello,

    Please take a look at the picture I have attached below.

    Three years ago after our sprinkler company winterized our sprinkler, we suddenly experienced strong water flood coming out from bottom test cock port. Water was also leaking from bottom valve. We tightened the bottom valve and water from both bottom valve and bottom test cock port stopped.

    The sprinkler company told us that sprinkler system (RPZ valves and test cock ports) is defective and we need to replace it.

    However, we thought it was strange that the water stopped, aftter we tightened the bottom valve. We thought it might have been because the bottom valve was not closed tight. Therefore, we did not use sprinkler during last year and we never had any flood issue any more.

    This year, I explained this to the sprinkler company, asked them to check the system and activate the sprinkler.

    However, they opened the top RPZ valve and water was flooding out. They still told me that our sprinkler system needs to be replaced. After their visit, we have water leak from top test cock port.

    They also told me that we do not have shut off valve so it needs to be installed.

    Here goes my question.

    01. Can someone explain to me what these 4 parts are? (top and bottom RPZ valves and top and bottom test cock ports)

    02. How can sprinkler company winterize our sprinkler system if we do not have shut off valve?

    03. Do you think we had water flood 3 years ago because our sprinkler system was defective? The water flood stopped after we tightened the bottom valve.

    03. Why do we suddenly have water leak again from top test cock port?

    I apprecate your help in advance!

    20130719_170207.jpg
  2. Sean Beck

    Sean Beck Plumber

    Messages:
    68
    Location:
    Toronto, Ontario, Canada
    The two blue handles are shut off valves which are part of the RP valve, and are used to isolate the valve so that the parts inside the valve can be serviced. The test ports are self-explanatory. They are used to test that the valve is working and not letting water from your sprinkler system into your potable water system.

    It would be best to install shut off valves upstream and downstream of the RPZ valve with unions so that the valve can be removed easily. The best way to winterize the system is to remove the valve and flush it out to make sure there is no water in it.

    The reason your leak will have stopped when you tightened the bottom blue valve is because you will have shut the water off to your sprinkler system which would mean the valve would no longer be under pressure. It probably started leaking again when you opened up the valve to de-winterize your system.
  3. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    26,293
    Location:
    Cave Creek, Arizona
    There are many conditions that can cause that valve to leak, and NONE of them are DIY situations. You have to test the valve using those four test cocks AND the proper instrument to determine which condition, or possibly conditions, you have.
  4. Gary Swart

    Gary Swart In the Trades

    Messages:
    7,308
    Location:
    Yakima WA
    Just to tag on to HJ's comments. Every place should require annual testing and certification of back flow prevention devices. Only some places actually do this. Usually it is a quick uneventfully processes, but sometimes a leak is discovered. The tester usually will have the necessary O rings to make the necessary repairs, and have you in safe operation. I don't know why every city does not do this, it's a simple enough process. My city checks a new installation the first time. After that, the city sends out a list of licensed and certified inspectors to homeowners who responsible to contact one of these inspectors and arrange to have his devices tested. When the test is completed, the inspector fill out a form, gives the homeowner a copy and sends the other to the city. The cost will vary by inspector, but usually it's about $35 plus repair parts if needed. If the testing is not done within the time frame allowed, the city will turn off the water until it is done. I doubt if many of us fail to get the testing.
  5. johnjh2o1

    johnjh2o1 Plumbing Contractor for 49 years

    Messages:
    1,142
    Location:
    South*East
    It's not an RPZ it's a DBL check. It's leaking because the test cocks are on.
    John
  6. JetSwet

    JetSwet New Member

    Messages:
    2
    Location:
    New York
    It is a double check. You can replace the test cocks and the shut off as well.
  7. Wet_Boots

    Wet_Boots Sprinkler Guy

    Messages:
    798
    Location:
    Metro NYC
    I hate to break it to you, but you need to replace the whole shebang with a backflow preventer that complies with New Jersey codes. Double Check Valve Assembly was okay in the 1980's, but the codes were revised more than 20 years ago, and the DCVA was no longer approved, and none of the old backflow preventers were grandfathered in - two devices are possible replacements - a Pressure Vacuum Breaker located on the outside of the house, at an elevation at least 18-inches higher than any sprinkler head or pipe downstream of the PVB - an RPZ located outside, at least a foot above grade, with no need to be higher than everything downstream

    Don't feel short-changed by the current rules. Since you live in a state that doesn't rigorously enforce testing of these backflow preventers, you aren't even aware of the likelihood that the pictured DCVA stopped functioning many years ago.

    For the sake of cost, and for preserving water pressure in the system, you would choose the PVB over the RPZ - if elevation of sprinklers relative to the house require you to use the RPZ, you will have pressure concerns, because an RPZ subtracts more than 10 psi from system pressure.
  8. Chrstine

    Chrstine New Member

    Messages:
    4
    Location:
    NJ
    Hi,

    I kept getting database and time delay error so I could not reply earlier. It turned out that it was because I was using Chrome.

    I appreciate everyone for replying! All your replies are helpful for me.

    Thanks to John, I learned a lot earlier and scheduled a service.

    Our water leak stopped after it was tightened. I have been informed that there is a possibility that our sprinkler company did not drain the water out completely, when they winterized, and that is the reason why we are getting flood or leak, after winterization.

    We are still getting rid of double check to make sure.

    Yes, I wish my state rigorously enforce the test. We moved into this house a few years ago and I did not know that the test could be done. It is really good to know that I can have the test for peace of mind.

    wet-boots, may I ask how you know ours is DCVA? Does current double check look different from DCVA?
  9. Smooky

    Smooky Member

    Messages:
    569
    Location:
    NC
    Here is a double check valve assembly that looks a lot like yours.

    MODEL 950XL DOUBLE CHECK VALVE ASSEMBLY

    http://content.zurn.com/web_documents/pdfs/installation/ISSM950.pdf

    http://www.zurn.com/Pages/ProductsList.aspx?NodeKey=407549

    http://www.zurn.com/Pages/ProductDetails.aspx?NodeKey=413965

    Most city codes in this area require a reduced pressure backflow assembly. This type of back flow preventer prevents backsiphonage and or backpressure. They have double checks with an atmospheric vent. Your back flow preventer does not have an atmospheric vent to prevent backsiphonage.
    Last edited: Jul 30, 2013
  10. JetSwet

    JetSwet New Member

    Messages:
    2
    Location:
    New York
    You will need the RPZ if there is antifreeze in the system and the system is hooked to town or city. There both check valve the RPZ is the function in which in case you don't have the same pressure on both ends and it will drain out before going back to the main road line.
  11. Wet_Boots

    Wet_Boots Sprinkler Guy

    Messages:
    798
    Location:
    Metro NYC
    It's a matter of terminology. What you have is known as a Double Check Valve Assembly, or DCVA for short. "Double Check" is for a different item, that has the same function, but lacks the testcocks and isolation valves of the DCVA, which are there for allowing testing and repair of the DCVA.

    I know yours is a Febco 805Y DCVA. I installed them in systems until the codes changed, making them unfit for lawn sprinkler system use. Lucky for me, I preferred the PVB right from the start, and didn't have the unhappy task of having to retrofit a lot of systems that were installed with DCVA's

    In terms of water pressure lost through the plumbing, exchanging the DCVA for a PVB is pretty much a straight swap. Exchanging the DCVA for an RPZ is a net loss of at least 5 to 10 psi so you may have to reexamine the sprinkler system performance after the change to an RPZ. Systems that were very marginal in performance sometimes had the DCVA exchanged for a PVB set at an awkward-looking height, in order to achieve the elevation difference that made the PVB functional, while not taking away any pressure needed to make the sprinklers perform properly.
  12. Gary Swart

    Gary Swart In the Trades

    Messages:
    7,308
    Location:
    Yakima WA
    Let's KISS. Keep It Simple Silly. All this discussion on type of device, cause of leakage, and on and on is pointless. It is a back flow device and requires a certified tester/repair person. You don't need to worry your head about brand, type, cause of the leak, or anything else. It needs servicing and it is not a DIY job PERIOD. Go back up to HJ's post and read and believe it.
  13. Wet_Boots

    Wet_Boots Sprinkler Guy

    Messages:
    798
    Location:
    Metro NYC
    That post is well intentioned, but somewhat misinformed, or at least mis-stated. The original device needs to be replaced, not tested or examined by anybody, and the plumbing WILL be reconfigured in the process. The role of the certified tester is not the same in every state, just as plumbing codes aren't the same in every state. New Jersey happens to be one state that historically never bothered with follow-ups on backflow preventer installations. New Jersey also has no prohibition against do-it-yourself-ers installing backflow preventers.

    There are some practical considerations involved in choice of backflow preventers. I preferred the PVB for the simple but compelling reason that it works on gravity, and gravity is more trustworthy than any certified tester on the planet. Only for reasons of sprinkler pipes and heads being located far higher in elevation than a PVB could ever be, did it fall to choosing the RPZ.
  14. Gary Swart

    Gary Swart In the Trades

    Messages:
    7,308
    Location:
    Yakima WA
    Ah yes, New Jersey: a Red state that doesn't concern itself with Federal laws especially concerning pollution, health, and safety. Hell, if you're not to to test it and make certain it is working, why even have one? I certainly realize that local customs vary, but all should require that a new back flow device be tested to make certain it is functioning properly regardless of whether installed DIY or professionally. Installation is grunt work. Testing requires training and test equipment. I don't claim to be an expert in this field, but I do know the state of Washington and the city of Yakima follow federal laws regarding back flow devices. I find it aggravating that code authorities can get so pissy about a wye fitting turned or not turned just so, and then just flat ignore Federal laws.
  15. Wet_Boots

    Wet_Boots Sprinkler Guy

    Messages:
    798
    Location:
    Metro NYC
    Hey, if you really want to see pissy muni plumbing officials, try telling them they're wrong about what is or isn't code, which I once did (and I was right and they were wrong) earlier in my career. I developed a more finely honed sense of diplomacy as time went on. {it was a source of satisfaction to later on see the muni official's desired plumbing configuration placed in a "illustrated plumbing code" with a big X across it, signifying that it was wrong}

    As for the idea that there is any federal law that details backflow requirements, it simply isn't so. The Clean Water Act is entirely free from details regarding backflow preventers for domestic plumbing. All that stuff is sluffed off on individual states, and they obviously handle things differently from each other. New Jersey placed a regional plumbing code into their construction code in the very early 1990's, and it allows a PVB or an RPZ for protecting the house plumbing from a lawn sprinkler system.
  16. Wet_Boots

    Wet_Boots Sprinkler Guy

    Messages:
    798
    Location:
    Metro NYC
    :rolleyes:
    Last edited: Aug 2, 2013
  17. Chrstine

    Chrstine New Member

    Messages:
    4
    Location:
    NJ
    Hello,

    We just replaced it with PVB.

    As a first time home owner, I sometimes get incorrect diagnostics, pay for unnecessary cost and then end up paying again to correct, because I am not knowledgeable. Therefore, It was necessary for me to understand our issue and choose right solution, because, this time, again, there were different diagnostics and various suggestions to resolve this matter.

    I appreciate you guys for helpful advice and detailed explanation!
  18. Wet_Boots

    Wet_Boots Sprinkler Guy

    Messages:
    798
    Location:
    Metro NYC
    I'm glad a PVB worked for you.

    Now that you have above-ground supply plumbing in your sprinkler system, you will want to have it winterized before any overnight freezing can damage things. The old practice of an indoor DCVA often went hand-in-hand with a supply line exiting below grade, and a system that could actually endure overnight freezes, allowing winterizing later in the fall.
  19. Chrstine

    Chrstine New Member

    Messages:
    4
    Location:
    NJ
    Yes, I will not just winterize in a timely manner but also make sure to have it tested every year.

    Thank you so much for your help!
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