Irrigation Head Scratcher

Discussion in 'Irrigation / Sprinkler Forum' started by DevilDog_RVN, Aug 12, 2019.

  1. DevilDog_RVN

    DevilDog_RVN New Member

    Aug 12, 2019
    We had a near miss with lightning at our house about 6 weeks ago. We lost 3 TV sets, a wireless router, a couple of Amazon FireSticks, and one desktop computer that was not behind a UPC.
    That may or may not have anything to do with what follows.

    A few days after the storm passed, we noticed that the sprinklers were no longer coming on. I checked for adequate water pressure past the main shut off valve for the sprinkler system and it was fine.
    • When I tested the overall system none of the zones would function from the controller. There was no voltage output from any of the zones.
    • I replaced the aging Hunter controller with Rachio Gen 3 and tested voltage at all 6 zones. All had appropriate voltage out at the controller.
    • No help. No sprinkler zones worked.
    • I isolated one valve to troubleshoot.
    • I removed the solenoid and activated the zone at the controller.
    • The solenoid did not actuate.
    • I cut the wires to the solenoid, took it to the garage, and plugged the wires directly into the controller. The solenoid functioned properly when that zone was activated.
    • I then tested for voltage at the cut wires at the valve box coming from the controller. Multimeter read 27 VAC at the valve box when that zone was activated.
    • I connected the solenoid (which functioned at the controller) to the wires that were shown to be hot at the valve box and the solenoid did not actuate.
    • On what seems to be an unrelated issue, when I tried to manually activate the same valve by rotating the solenoid a quarter turn with the water supply turned on, nothing happened.
    • I have not disassembled the valve to check the diaphragm yet because whatever is going on there can't have anything to do with the solenoid.
    I find it hard to believe that all 6 zones have independently failed downstream from the controller at or about the same time, so I am totally baffled.
    Perhaps the coincidence of a hydraulic failure in the valve (if that's what it is) just happened to occur simultaneously with this bizarre electrical phenomenon. That also seems very unlikely.
    I suppose one could still measure 27 VAC at the valve box with a nearly severed wire that couldn't deliver enough current to adequately energize the solenoid windings, but that's kind of hard to imagine as well.

    I sure hope somebody here understands these systems well enough to tell me what the hell is going on!
  2. drick

    drick In the Trades

    May 16, 2008
    Given that you had a pretty serious lightening strike, and based on all the testing you already did I think you are on the right track with the damaged wiring. I know you said you read 27 VAC at the vale box wiring with the solenoid removed but what does your meter show if you connect it at the box with the solenoid still connected? Does it still read 24-27 VAC? Either the voltmeter will read 24-27 VAC and the solenoid WILL activate or the voltmeter will not read 24-27 VAC and the solenoid WILL NOT activate. Based on your testing so far I'd expect the latter which indicates damaged wiring. (Just a note about digital volt meters. They suck at reading Zero volts so if that's what you have at the valve the reading on the meter could be all over the place.)

    Also I know you said you replaced the timer, but did you also replace the timer's transformer? A bad transformer can test OK with no load, but fail to deliver 24 VAC when under load. I'm still thinking it the wiring since your solenoid worked when connected directly to the timer, but its something to consider.
    Last edited: Aug 12, 2019
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  4. HudsonDIY

    HudsonDIY New Member

    Jun 19, 2019
    Hudson, Florida USA
    If lightning ran up those lines to your valves you likely have a mass of wires fused together somewhere along the way especially if that was the lightning's source to ground.

    We had a strike on the metal roof of our screen room a few years ago which literally melted 1/2 inch off an aluminum box beam, ran down the wall to an outside light, blew through the inside of the wall crossing the room to my desk and blew up everything directly and indirectly connected to the cable TV coax. Thankfully #1 The house did not burn to the ground #2 No one was home.
  5. WorthFlorida

    WorthFlorida Broad-Wing Hawk

    Oct 28, 2009
    Orlando, Florida
    So far you have done everything correctly and by checking the solenoid at the controller definitely points to the wiring leaving the controller.

    You might get lucky and only the common wire is burned open. If there is only one common wire leaving the controller it is branched off to the other valves or daisy chain to every valve. If it opened between the controller location and the first valve, nothing will work.

    You need to go to the first valve where the common wire goes to. At that valve box open both the common and the wire feed for that zone. Then check voltage and ohm readings. If they read good only connect this one solenoid to the common and its zone wire. If this zone works connect the daisy chain common wire and try again. If it works or not you’ll know which direction to go for.
    Last edited: Aug 18, 2019 at 11:47 AM
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