SPRINKLER TALK FORUM - You Got Questions, We've Got Answers

If I understand you correctly: The zone in question OHMS out fine, but the remaining zones read 0 OHMS?



If your multimeter is showing 0 OHMS, it usually indicates a broken wire. Most likely the common.

Step 1: Check that the wire is well to connected in the controller

Step 2: OHM out the selenoid at the selonoid wires (make sure you didn't replace the old one with a bad one)

Step 3: Check the selenoid wire connections in the valve box (Probably where you'll find the problem, being that you recently disconnected these wires). Make sure you didn't accidently grab the wrong end of the zone wire. Also make sure your common wire is wired in correctly. The only selonoid that has only one common wire is the one at the end of the wire, so make sure that both ends of the common are making contact.



If you have multiple valves in a single valve box, make sure one wire from each selenoid is connected to the common.

Then yes, there is a problem with the zone wire or the common for that valve. Is the valve in question at the end of the multistrand wire or is it between two other valves? A simple way to check is to look at the wire nuts for the troubled valve and see how many common wires go into the wire nut. A valve at the end of the multi strand will only have one common wire and a selonoid wire in the wire nut. A valve in the "middle" of the multistrand will have two common wires and the selenoid wire. We need to figure out if it's the common or the zone wire that is broke.



Another thing you could check is the voltage of the bad zone at the controller. Turn on that zone at the controller, and using one of the selonoids, touch one wire to the common post and the other to the zone post. You will more than likely hear the selonoid activate. I advise using the selonoid, because voltage readings don't necessarily mean you have the power to activate a selonoid. If you would like to check it with your multimeter, you should have readings of 24-26 volts.



Conversly, out at the valve box we'll use your multimeter to check the voltage of your zone wire. Undo the selonoid wire and zone wire. Stick one probe into the ground and touch the other probe to the zone wire. You should read in the neighborhood of 24-26 volts.



If you read values lower than these it is safe to assume you have a problem with your zone wire. The only way it could be a common wire problem is if the valve in question is at the end of the wire, being that all other zones show resistance.



Once you make any repairs, check your work with the selonoid.

I was hoping Boots would answer this question. He's the one who always recommends measuring the continuity of the wiring. A reading of 0 doesn't indicate a broken wire. It means no resistance. A broken wire would read infinity. Disconnect the ground wire from the controller. Put your meter on the lowest setting and check again. There should be a reading because of the solenoids. Should be somewhere between 20 and 60.

I might have chimed in sooner, but a reading of zero ohms is, in theory, a dead short, but those aren't seen very often in sprinkler wiring, when you use digital multimeters. Modern controllers would cut themselves out when feeding a dead short, and likely display an error message.