RPZ or double-check?

Discussion in 'Irrigation' started by jcom, Apr 11, 2005.

  1. jcom

    jcom LawnSite Senior Member
    Messages: 791

    I am interested in your experiences with these two devices as I will be installing one or the other in a system soon.

    Can either be blown out through the unit? Will they drain if drains are provided on either side as I don't want either to freeze on those nights when it is only into the 20's?


  2. DanaMac

    DanaMac LawnSite Fanatic
    Messages: 13,226

    You can blow out thru either device, BUT it would be better to put in a connection to hook up to after the BP and not hook to the testcocks. Put a drain on both sides of the BP. But that doesn't mean it won't freeze just by draing them. The Febco 825y RP (DCV also I think) holds water in the area that the second check valve is located and will split the body if not taken apart and drained.
  3. jcom

    jcom LawnSite Senior Member
    Messages: 791

    Will the water be removed when blown through? How difficult to take apart and drain manually?

    Thanks for the response. I have used PVB's and now have an instance where it is necessary to install one of the others

    John :waving:
  4. jerryrwm

    jerryrwm LawnSite Bronze Member
    Messages: 1,274


    Quick question. In your area, when you take apart an RPZ like that, do you have to have it tested/certified when it goes back on line?

    We had a good freeze here this year - imagine Corpus Christi, TX with 6" - 8" of snow and 28 degrees on Christmas Day! First time in over 110 yrs.

    Anyway, we are still finding busted PVBs as people are now turning on the systems. When replacing the bonnet assy, we are required to test/cert. the device again.

    Jerry R
  5. bicmudpuppy

    bicmudpuppy LawnSite Silver Member
    Messages: 2,781

    Hey guys, if your backflow certified, go back and remember your training.........If the device was removed from service for ANY reason, you must insure it is in proper working order when you restore it to service. That means a test. You don't necesarily have to report or return a test sheet, but by uniform code and your certification training, you are liable for its function at the time you return it to service. Now, want to really stir a fuss........that's why my spring turn ons are priced less than my competition.....the backflow cert is FREE. Our code enforcement here is so poor that I have turned in FAILED sheets on devices that the customer wouldn't pay to fix (yes, I left them in the off state upon failing), and city water does nothing about it. If you don't test, you get a second and maybe a third threatening letter, but they have NEVER shut anyones water off. And that includes non-irrigation as well. I know a property whose fire DC's have been failed and not repaired for over 5 years. My policy is that I test them for free until they fail, then I expect my customers to pay for the re-build to keep their equipment up to code, or they go in search of a paper hanging irrigator...my part of the country is full of them.
  6. Wet_Boots

    Wet_Boots LawnSite Fanatic
    Messages: 50,746

    ...so hopefully the existing system can sustain that much loss of pressure. The psi loss for a double check valve assembly is closer to 5 psi. You can blow out a sprinkler system through a double check valve, no problem. An RPZ is more of a winterizing problem, since many of them have sections that won't be empty of water until you physically dismantle the valve. (these things were designed in Sunny California, where they don't worry much about freezing water) - it isn't rocket science to dismantle and reassemble the RPZ. As annoying as an RPZ can be, it might make sense to use it instead of a DCA, because when codes get tightened, as codes will, the DCA is likely to not be an approved device, and old DCA's may not be 'grandfathered' in.
  7. MOlawnman

    MOlawnman LawnSite Member
    Messages: 161

    ALL BP's must be tested and certified every year regardless if it was taken out of service or not. The water department here is very strict..they will shut you off and lock the meter for non-compliance of the backflow law. Backed up by Missouri DNR.
  8. bicmudpuppy

    bicmudpuppy LawnSite Silver Member
    Messages: 2,781

    Yep, Missouri isn't to trifle with, but cross the line into KCK and see what a mess they've made of things. The rest of the state is almost as screwed up too. The area I was refering to as not enforcing any backflow code is Lawrence.

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