Severe water hammer/slow close valves

Discussion in 'Irrigation / Sprinkler Forum' started by slb, Jul 12, 2005.

  1. slb

    slb New Member

    Messages:
    48
    Location:
    San Francisco North Bay
    Our back yard lawn sprinklers make a loud banging sound whenever they shut off. It's been this way since we bought the house four years ago, but I just now got around to investigating. I now realize that we are experiencing severe water hammer. There are eight sprinkler heads on one anti-siphon valve (too many?). I tried reducing the flow, but to significantly reduce the hammer, the flow had to be so low that the lawn was not being watered properly.

    I did some research and found some Hunter valves (type HPV) that claim to close slowly to eliminate water hammer. Do these work? Any other suggestions (other than digging up the lawn to add zones)?

    Regads,
    Steve
  2. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    22,139
    Location:
    New England
    Put in an arrestor near the supply.
  3. slb

    slb New Member

    Messages:
    48
    Location:
    San Francisco North Bay
    The local hardware stores only have the small arrestors with compression fittings for use with dishwashers and icemaker hookups. Can you recommend an arrestor for use with sprinkler systems?

    Regards,
    Steve
  4. captwally

    captwally New Member

    Messages:
    102
    Location:
    Florida
    The cure may be more simple than you realize. However, it does involve disassembly of the valve that is hammering. Irrigation valves are of a diaphraghm type that use the water pressure to close it, and an electric solenoid to open it. The water pressure must bleed to one side of the diaphragm to force it closed, and if the rubber is old and stiff, it can cause the effect you are seeing. If the orifice through which the water pressure must bleed to force the valve closed is restricted by debris, you can also see this happen.

    Note the brand and model of the valve, and ask your local irrigation supply house for a rebuild kit. There are typically about six stainless screws that hold it together, and rebuilding is quite an easy DIY project, if you pay attention and use common sense. Good Luck!
  5. slb

    slb New Member

    Messages:
    48
    Location:
    San Francisco North Bay
    Thanks Wally. The anti-siphon valves are Orbit brand. They look like the same valves that sell <$10 at the local HD. I'll see if I can locate a rebuild kit, but it might be easier just to replace the whole valve. Are some brands better performers than others (I can buy Toro, Lawn Genie, Orbit and Champion valves locally and other brands on-line)? Any experience with the Hunter valves I mentioned above?

    Regards,
    Steve
  6. captwally

    captwally New Member

    Messages:
    102
    Location:
    Florida
    Good deal, sib. The realm of irrigation pieces, parts and accessories can be a confusing one, and it's all about the almighty dollar. you are correct in that an "Orbit" valve is basically an economy brand manufactured exclusively with price in mind, not quality.

    Hunter, Toro, RainBird, etc are all GREAT products but be careful! The stuff they sell at your local Home Improvement Warehouse store are not of the same quality as what your lawn irrigation professional uses. Typically the commercial products aare manufactured here in the USA to a very high standard of quality (and obviously a higher price tag.) And the cheaper ones are mass produced overseas by some poor guy making $12 a year, and sold to the large retail chains for more profit and the fact that many people will buy it simply because it is less expensive, though it does have the High Profile name. A few extra dollars are well worth it in a case such as this. Best to find a commercial supplier who will sell to the public. Good Luck
  7. PEW

    PEW DIY Senior Member

    Messages:
    487
    If you can't find anything locally there are several suppliers on the net.

    Paul
  8. doctor sprinkler

    doctor sprinkler New Member

    Messages:
    2
    You may need a pressure reducing valve to slow down the speed of the water through your pipes. You really should'nt have more than 50 psi to the heads as that is generally the optimal pressure for rotors and sprays. Water travelling to fast will also damage you pvc fittings and valves over time.
    Hope that helps.
Similar Threads: Severe water
Forum Title Date
Irrigation / Sprinkler Forum New plumbing created water hammer noise in 3 irrigation zones Apr 10, 2014
Irrigation / Sprinkler Forum Huge water bill - need help Nov 19, 2013
Irrigation / Sprinkler Forum Propane Hose as Water Line? Sep 24, 2013
Irrigation / Sprinkler Forum No hot water when pro-installed irrigation system is running Jul 27, 2013
Irrigation / Sprinkler Forum Pushing lake water 500' through 1" sch 40- Uggh Jul 1, 2013

Share This Page