1. Can’t make it to the GIE+EXPO 2017?
    LawnSite brings the trade show floor to your fingertips with our new GIE+EXPO 2017 Sneak Peek video series debuting now in the Lawn Mowing forum.

    Dismiss Notice

PVB question

Discussion in 'Irrigation' started by Dirt Boy, Aug 29, 2011.


    Messages: 18,668

    Okay I'll post the whole scenario and see what you guys think. Not a well man. Think I mentioned that before.

    Messages: 18,668

    The original post
    I had a customer tell me I was unprofessional because I could not gurantee getting rid of the water hammer in a existing system with a well pump. About 50 psi and roughly 10-12 gpm

    Entire system was 3/4 schedule 40. Zones were exceeding 13 gpm. They did not want to spend the money for a new system. I removed 46' of 3/4 from the poc, installed 1" and 1"pvb. I renozzled the heads to get to 10 or less gpm, which increased his arc to get head to head coverage. It minimized the hammer. I then added 180' of 1" to get to the other side of the house and installed his existing valves for the already installed zone pipe and spray heads. I renozzled the sprays, a very small area and he didn't like the way water came out of the 5 half nozzles. He wanted more water in the area. Needless to say, he told me he was happy the hammer was nowhere near as bad as it was, however the wife sung a different tune the next day when I went to get paid.

    My response
    Looks like you got everything below 5fps. If nothing else a shock absorber at the washing machine connection might help a little more. Griswold valves claim to avoid water hammer issues. As a MV it might help. Is the hammer at startup or when zones change? I'd try to deal with the husband obviously.

    OP response
    at start and between zone changes. I also recommended switching valves as I know dv100 are fast closers. I was dealing with the husband until I went to the house to get paid, I gave him a time I'd be there and I passed him on my way to his house. I know who wears the pants in that house.

    My response
    I'm getting curious now. My troubleshooting gene is kicking in. Which controller are you dealing with? Is there any chance the pump is shutting down between zone changes? Is a pressure activated pump?

    OP response
    There is no relay for the timer. The timer the homeowner installed is Hunter x-core. The pump has a pressure tank which cycles according to the well tech. every 45 seconds. I did recommend installing a flow switch and pressure switch for the system to have continual even flow no matter if they were irrigating or using house water. The rid-o-rust tank is connected to a pump relay.

    Then I came here
  3. AI Inc

    AI Inc LawnSite Fanatic
    Messages: 26,616

    weird, actualy a hunter closes a lot faster then a 100 dv.
  4. bcg

    bcg LawnSite Bronze Member
    from Tx
    Messages: 1,865

    So the pump is short cycling every 45 seconds or so? If so, the first thing I'd do is install a Cycle Stop Valve to fix that problem. Odds are that fixing the short cycle will also help a great deal with the water hammer. Honestly though, with a pressure tank, it should be absorbing a lot of the hammer so it would be a good idea to also check the air pressure in the tank and recharge it if needed.
  5. Wet_Boots

    Wet_Boots LawnSite Fanatic
    Messages: 50,261

    echo the Texan - stop the cycling and check the pressure tank

    ...and don't piggyback on other threads - you piker
    Last edited: Aug 30, 2011

    Messages: 18,668

    I passed that on. THKS Always open to more though.
  7. Mike Leary

    Mike Leary LawnSite Fanatic
    Messages: 23,097

    Ouch!.....the MAN makes a true statement.:clapping:

    Messages: 18,668

    Only on well stuff. No piggybacking other than that. It gives me a chance to learn a few things.
  9. Sprinkus

    Sprinkus LawnSite Silver Member
    Messages: 2,296

    Is it a VFD drive or a pressure switch?
    The small pressure tank make me think that it's using a VFD or a cycle stop valve/pressure switch combination.
    If it' a VFD then the settings could possibly be able to be changed to fix the problem.
    Pictures would be helpful.

    Messages: 18,668

    Can't answer that. I think he had a falling out with the customer so we may never know.

Share This Page