Troubleshooting Doublers

Discussion in 'Irrigation' started by Planter, Nov 3, 2005.

  1. Planter

    Planter LawnSite Member
    from Utah
    Posts: 214

    I have a doubler that is giving me trouble. It won't kick on either zone. The valve next to it is OK, three valves in the box, so i know the common is alright. I get an open line on the ohms reading at the clock when the doubler is connnected (both stations).

    Turn off time and remove the connectors at the double, untangle the wires and fire each valve with the station master, they all come on. I remove the doubler and take a volt reading on the station master. I get 20 volts and some change. I connect the station master to the doubler and fire it. I check from the common to the valve wire that is hot, I get 11 volts. I know I should check from the clock, but it's way back there.

    The question is:
    Should I get a standard ohm reading for the valve at the clock on the leg that is doubled?
    Is 11 volts what the doubler should be reading with the station master porering it?
    I wired the common and station wire together and get 2.6 ohms, is that about right? Past experience tells me I should be somewhere around 5.
     
  2. PurpHaze

    PurpHaze LawnSite Fanatic
    Posts: 5,496

    I'm not up on the finite ohm aspects of the doubler (Wet Boots is pretty good in this area). We've used them in the past and I really don't like them. They always seemed to be more trouble than they're worth. We've even had them "stick" to where they needed a rap on them to get them working.

    I'm assuming now that this is one that was working and now doesn't... or is this a new install of the doubler? Seems to me that you should be getting more voltage through the doubler itself. The controller puts out 24v theoretically and then the voltage decreases depending on resistance (wire size, length of run, connectors, etc.) until it reaches the valve solenoid. It takes a minimum of somewhere around 9v to actually activate a standard solenoid. Your wiring is intact because you can fire the valve through it without the doubler and assuming that you have everything else right (including jumper at the clock) it shoulld work.

    I have a couple of doublers at the shop. I'll look at the paperwork when I get there and post later.
     
  3. bicmudpuppy

    bicmudpuppy LawnSite Silver Member
    Posts: 2,781

    Your getting zero ohms through the doubler........that means the doubler's solenoid/coil is toast. Your only getting 11 volts past the doubler.........because the doublers solenoid/coil is toast. A doubler is simply a solenoid fired switch that "flips" each time it recieves power. To correctly operate a doubler of this type, the instructions tell you NOT to wire this device to consecutive zones. You need to run another valve in between the stations doubled. The reason for this is so that you don't risk the device not sensing the switch and therefore not changing zones. In recent years, I have used the R-Co "add-a-zone" instead of a traditional doubler. This device uses a filter at the controller to add a signal or frequency to the station wire in use. The field portion then senses that frequency and allows current to the correct wire. No solenoid for increased ohms or significant power usage. Also, the "add-a-zone" will allow both wired valves to operate if power is fed through both sides of the filter. This means (even though I don't recomend it and feel it is a last resort) that you can double a wire to run a regular zone valve and the master valve and everything works like it should. Hope that helps. Good luck. I never met a doubler of any kind I couldn't hate :)
     
  4. Wet_Boots

    Wet_Boots LawnSite Fanatic
    Posts: 48,003

    I wouldn't mind seeing a photo of a dead doubler cut open. I always wondered if my guess as to what was inside one was accurate.
     
  5. PurpHaze

    PurpHaze LawnSite Fanatic
    Posts: 5,496

  6. PurpHaze

    PurpHaze LawnSite Fanatic
    Posts: 5,496

    The other thing we had to ensure was that the two zones were compatible as far as watering time. Although the doubler can be used for multiple valves with varying water times we never doubled more than two and always made sure the two zones would be receiving the same amount of watering. We experienced problems with power outages and other things that messed up the timing and would switch the valves as to when they fired sequentially. :dizzy:
     
  7. PurpHaze

    PurpHaze LawnSite Fanatic
    Posts: 5,496

    I looked and discovered I have a dead one at work. Maybe I'll put it under the saw tomorrow and take some pictures. :p
     
  8. PurpHaze

    PurpHaze LawnSite Fanatic
    Posts: 5,496

    Had the time to carefully saw open a dead doubler. Appears to be an electro-mechanical switch surrounded by watertight ABS.

    Doubler Interior WP-01.jpg

    Doubler Interior WP-02.jpg

    Doubler Interior WP-03.jpg

    Doubler Interior WP-04.jpg

    Doubler Interior WP-05.jpg
     
  9. Wet_Boots

    Wet_Boots LawnSite Fanatic
    Posts: 48,003

    Bingo - that's a Potter & Brumfield 'latching relay' - I once bought one of them and sealed it into a container made of a couple of sch 40 caps and a bit of pipe, and figured it was as good as a Doubler. It didn't last very long. I think it might have done better if I could have vacuum-sealed it, but face it, underground is not the place for electromechanical devices, no matter how you enclose them.
     
  10. Planter

    Planter LawnSite Member
    from Utah
    Posts: 214

    What you have pictured there is what I thought I'd find when I cut mine problem child open. Not so! Mine has a circuit board with a couple, resisters, capaciters, and switches (my spelling on this is really bad!)

    I'll shoot a picture of mine and post it tomorrow.
     

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