Blowing Controller Fuses

Discussion in 'Irrigation / Sprinkler Forum' started by Planojack, Jul 1, 2008.

  1. Planojack

    Planojack New Member

    Messages:
    7
    My 6 zone system blows a fuse every time it goes to zone #4.
    Is this a bad solenoid??
    Thanks:confused:
  2. jimbo

    jimbo Plumber

    Messages:
    8,997
    Location:
    San Diego
    Either the solenoid itself, or a shorted wire, caused by shovel in the garden, hungry squirrel, etc.
  3. Joerg

    Joerg New Member

    Messages:
    138
    Location:
    Califonia
    If you have a multimeter set it to the 200ohm range, turn power to the controller off, disconnect the zone #4 wire and measure into that wire and solenoid common. Should normally read 15 ohms or higher. If it does and the fuse still blows the solenoid may have a winding short inside and needs to be replaced.

    Or simply disconnect at the valve and see if it still happens while the solenoid is disconnected.

    If you don't own a meter yet sometimes Harborfreight has those digital meter deals for $2.99. Can't beat that, those things work. Got five of them here.

    Regards, Joerg
  4. Planojack

    Planojack New Member

    Messages:
    7
    Blown Fuses

    Thanks Jimbo & Joerg for you suggestions. I think i have a bad solenoid on zone 4. I can run the zone manually thru the bleed valve but it blows if in the circuit when I run it with controller. For now I have taken the hot wire out - Trying to decide if I am smart enough to change out the solenoid or call a contractor?
    Again Thanks,
    Jack:rolleyes:
  5. jimbo

    jimbo Plumber

    Messages:
    8,997
    Location:
    San Diego

    This is one job where no one here is going to give you the "call a contractor" routine. You can do this!

    Solenoids just unscrew from the top of the valve. Try to identify your brand and model of valve, then go to the hardware store or a landscape supply company to get the exact replacement. Although the voltage is low, just temporarily unplug your timer while you are working. Cut wires and strip, join with a wire nut, preferably a silicone filled nut. Otherwise, wrap the nut with electrical tape to keep water out. That's about it. It doesn't matter which wire goes to which side of the solenoid..
  6. Joerg

    Joerg New Member

    Messages:
    138
    Location:
    Califonia
    But before you run to the HW store untie one solenoid connection at the valve and let the controller try to turn it on. If the fuse doesn't blow, yes, that would be a defective valve. As Jimbo said this is easy to fix. If it does blow you have a cable short.

    It can happen that a solenoid alone costs more than a whole new valve. Then I'd buy the whole valve because then you'll get a spare diaphragm for free and some day you'll need one.

    Regards, Joerg.
  7. Planojack

    Planojack New Member

    Messages:
    7
    Cen-Tech Settings for Ohms readings

    I purchased the Cen-Tech 7 Function Digital Multimeter at $2.99 but don't really know how to set it for testing from the controller. Can you help?
  8. Joerg

    Joerg New Member

    Messages:
    138
    Location:
    Califonia
    To measure loop resistance? Ok, plug the black probe cable into COM, the red into V-ohms-mA (the middle jack). Unplug supply of zone controller. Remove the wire for zone #4. Switch meter dial to the 200ohm range which is at the six o'clock position, turn yellow switch on. Hold probes together to see if it works, mine shows around 0.3ohms. Poke black lead onto the common terminal of your controller, often called COM or 24V-RET. Press the red one firmly onto the wire and see if you get around 15 ohms reading. Or a few ohms more if you line is really long. If the meter shows only very few ohms you have a short.

    But again, you may also have a solenoid that has just a few turns shorted internally. If you untie the solenoid at the valve and then the fuse doesn't blow anymore that's most likely the problem.

    Good luck,

    Joerg
  9. Joerg

    Joerg New Member

    Messages:
    138
    Location:
    Califonia
    Just one more hint, can save lots of digging time: If the meter shows you do have a cable short you can measure into the cable from the zone controller end and then again from the valve end. Make sure you really get a good contact from cable to probes. Might want to use pliers to gently press the wires on.

    Example: It reads 1.5ohms at the controller and 1ohm at the valve. Now subtract the meter's own internal resistance as measured when you press both its probes together, in my cases usually 0.3ohms. That makes the controller side 1.2ohms and the valve side 0.7ohms. The ratio in this example would mean your short is at about 37% of total cable length when starting at the valve. Now it won't be very exact but at least it gets you close. Or maybe it jogs the memory "Oh, that's roughly where I took out the old tree stump last week".

    Regards, Joerg
  10. Planojack

    Planojack New Member

    Messages:
    7
    Thanks Jeorg - I set up as you instructed and turned it on:
    Got a 00.1 reading - When I touched probes together I got 00.0 reading
    I checked zone 4 and got 00.1 to -00.0 reading
    other zones read 00.1 to 00.0 Must be a bad meter?
    I did identify the valve as a Richdel R204A and the Solenoid as a R811 Now if I can find the parts. Also ran the 9Volt battery test in the Cen-Tech book and got 0.0 reading
    Also - With zone 4 out of the controller it runs fine through all the other zones. Is this telling me anything about zone 4 solenoid???
    Thanks Again,
    Jack

    PS-Called Cen-Tech 800 number severial times and its always busy
  11. Joerg

    Joerg New Member

    Messages:
    138
    Location:
    Califonia
    That looks like a bad meter. I had a bad one as well, out of the five I bought. Just call Harborfreight. They sent me a new one free of charge and told me to throw the bad one away.

    Anyhow, connect zone 4 again but untie one solenoid wire at the valve. See if the fuse still blows. If not then you cable run is fine and the valve is bad. If it does blow you have a bad cable (a short).

    Regards, Joerg
  12. Planojack

    Planojack New Member

    Messages:
    7
    Jeorg

    I changed out the solenoid today:
    Turned off power to controller
    Turned off water to system
    spliced in new solenoid
    Turned on water slowly and Valve started running?
    Checked the flow control and its off
    Valve is running all the time that water is on??????????????????????????
    Still haven't reconnected to controller?
    Also-I noticed an "O" ring under the old solenoid and put it back in with new solenoid
    Jack
    Last edited: Jul 21, 2008
  13. Joerg

    Joerg New Member

    Messages:
    138
    Location:
    Califonia
    Are you sure it was the right solenoid? Does the plunger and spring in it look the same as on the old one? Valve manufacturers seem to be a bit haphazard in that respect. For example, our old 100E brass valves came in at least two very different solenoid versions, yet both valves are called 100E.

    This is hard to say from the distance. If the bleed screw is tight and the diaphragm is not leaking (assuming you didn't touch that) it almost sounds like a wrong solenoid type. On most of them there is a small rubber piece at the end of the plunger which closes a tiny hole. This must reach down far enough to be able to close that hole, upon which the valve should shut off. You can see one in the second picture here:

    http://irrigationtutorials.com/faq/repair-valve.htm

    Regards, Joerg
  14. Planojack

    Planojack New Member

    Messages:
    7
    Jeorg -
    The new solenoid has a "captive hex plunger feature" which retains the plunger but I learned from the irrigation
    supply company they must be removed at times to make the solenoid work. I removed it and the valve started working.
    Ran auto & manual test from controller and no problems. I feel like I should get some kind of certificate but
    I will settle for the feeling of getting it done. Which by the way would have never happened without your
    advice and patience. I have learned a lot!
    Thanks Again,
    Jack
    Last edited: Jul 22, 2008
  15. Joerg

    Joerg New Member

    Messages:
    138
    Location:
    Califonia
    Hooray, it works! Wish I could say that for my issue here (water hammer) but I'll get around to it soon.

    With a situation like this a good thing to ask yourself is how old are the other valves? Same vintage and model? Sometimes it may be worth to do preventive replacements on the others as well, especially in case the old plunger/spring assembly was quite corroded. If a valve remains open and you aren't home that may not be cool. We had it happen about a month ago but luckily we were home. My wife noticed a serious lack of water pressure and then I saw that the zone that was running two hours ago when I got the newspaper was still running ...

    Well, at least now you have a new tool, the multimeter. Those come in really handy if something else croaks. A light on the car quit, doorbell doesn't work, check if there is juice left in a battery, not enough signal from the TV coax, a telephone is dead and so on. It's easy to obtain learning hints on the web, just be careful and stay away from 120V or 240V mains wiring.

    Regards, Joerg
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