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Beartooth
02-27-2007, 12:28 AM
I have ran into a problem with a large system we installed about five years ago. Last fall, two zones started to come on simultaneously. I have isolated the problem to the point that I know that the two control wires are either making contact out in the field or they are going to ground out in the field. The wire is 18 guage multi-strand with 13 conductors. There was a lightning strike about a month or so before this condition appeared. Is there an efficient way to find out where the two wires are making contact?

justgeorge
02-27-2007, 08:19 AM
Are all 13 strands in use? If not switch one or both of the problem zones to spare wires. I always run at least 1 extra wire than what is needed in case of problems like these.

George

SprinklerGuy
02-27-2007, 08:24 AM
If there was a lightning strike I would be more inclined to blame the timer than the field wiring.

I know you said you had it isolated....however, have you checked the timer? Sometimes lightning strikes to strange things to solid state controllers.

Start there, IMHO....

Duekster
02-27-2007, 08:32 AM
Check the ohms on the strands and across the zones in question. This can help determine if the controller or the wires.

There are several wire trace tools available to you but as someone said, eliminate the controller first.

Beartooth
02-27-2007, 10:23 AM
The controllers have been eliminated, there are no extra wires available. The problem is 100% in the field wiring as I stated in my original post.

Wet_Boots
02-27-2007, 10:40 AM
If you had two zone wires shorted together out in the field, it might be possible to disconnect those two zone wires at the controller and at the solenoids, and run a tracer signal through the two wires. In a perfect world, the signal would enter one wire, cross over at the short, and return through the other wire. A locater could then pinpoint the fault.

Beartooth
02-27-2007, 11:08 AM
What type of tracer and locating device do you suggest?

SprinklerGuy
02-27-2007, 11:20 AM
Please satisfy my curiousity and explain how you eliminated the controller?

Thanks....always learning.

Beartooth
02-27-2007, 11:54 AM
In order to eliminate that the controller was causung the problem, I physically removed the wires from the controller and connected them to a new controller. When I did this, we had the same problem. After the lightining strike, by the way, the controller was replaced. So we are dealing with a controller(Rain Bird ESP 16lx) that is less than a year old. Hopefully this will help clarify the situation to you. Thanks for the help!

Wet_Boots
02-27-2007, 12:08 PM
The Tempo/Progressive 521 is probably the most popular locater in the sprinkler biz, and there are several other makes. You can probably rent one. If you have a good digital multimeter, you might do a resistance check to see if any other zones might be faulty, or grounded out somewhere.

PurpHaze
02-27-2007, 10:51 PM
The only thing similar I've run into is when we had gophers get two of our control wires at the same spot. This was 14 gauge single strand and not multi-strand like you have. Two valves would come on simultaneously for a little while and then they stopped working altogether. Found the two wires bare and touching at the gopher attack location. However, we did not find this by using the 521 locator, rather by using their ground fault locator (whatever modle number it is). It found the problem because not only were the wires touching each other but they had earth contact which created the earth ground. If your wires are touching somewhere but still encased in the multi-strand outer insulation I'm not sure this would work for you.

SprinklerGuy
02-28-2007, 08:14 AM
Pulsar....Pulsar....Pulsar.....Pulsar......ouch!

bicmudpuppy
02-28-2007, 02:31 PM
Ok, unless these two valves are the first two valves in the multi-strand path, I am having trouble accepting the "no spares" concept, but if you truly don't have the ability to use the multi-strand path as spares, you could use an R-Co Add-a-Zone to either double the existing crossed wires, or two add-a-zones to split two working wires into four seperate zones. At about $100 each, add-a-zones are not my first choice, but your problem as described could cost you more than $200 in time and effort with an experienced tech and all the toys at your disposal.

Dirty Water
02-28-2007, 04:20 PM
Yeah, if they aren't the first two valves in the circuit, then splice the two zone wires that are effected to the zone wires that ran to the first two valves, since the wire after those valves is now unused.

Unless your one of those oddball contractors that would splice both ends of the hot wire to a valve, I found that out in the field on occasion, and I never understood the logic there.

bicmudpuppy
02-28-2007, 05:33 PM
Yeah, if they aren't the first two valves in the circuit, then splice the two zone wires that are effected to the zone wires that ran to the first two valves, since the wire after those valves is now unused.

Unless your one of those oddball contractors that would splice both ends of the hot wire to a valve, I found that out in the field on occasion, and I never understood the logic there.

Yes, but even then, it is still workable to re-work a splice or two and use the existing wire.

Beartooth
02-28-2007, 09:10 PM
The hot wire splices @ each zone valve are wired properly. This is the first thing I checked because I also thought that possibly both wires were spliced to the valve control wire. No such luck! The reason this is such a pain in the @$$ is because we're talking about a 3 acre system. There is a lot of wire in the ground. Do you think the lightning strike could have fused together just two wires? I am trying to figure out why after so many years this condition just appears out of nowhere!

ed2hess
02-28-2007, 09:22 PM
Should be able to detect shorting between two wires with a regular ohm meter. Disconnect the gnd from both in the valve box and measure resistance at the controller between the two hot wires.

PurpHaze
02-28-2007, 09:51 PM
The reason this is such a pain in the @$$ is because we're talking about a 3 acre system. There is a lot of wire in the ground.

This is a small system to me. :)

Do you think the lightning strike could have fused together just two wires? I am trying to figure out why after so many years this condition just appears out of nowhere!

I have no experience with lightening strikes (not common to our area) but based on the pictures that some guys have posted after lightening strikes in their areas I'd be assuming that a whole lot of fried wires, solenoids and even the controller would be evident.

Wet_Boots
02-28-2007, 10:04 PM
Prairie Dog invasion? Lightning is a wild card. Replacing all the outdoor wiring should not be completely discounted as a possibility from the worst of lightning damage. You need a locator. If you've been getting by without one, well, too bad. Time to buy.

PurpHaze
02-28-2007, 10:06 PM
Didn't someone from Texas or the Florida panhandle post one time about armadillos creating wiring problems??? :laugh:

londonrain
02-28-2007, 10:17 PM
We have chipmunks and ground squirrels in my area and they use the trench as a tunnel. If the field wires are in the way they chew the outer sheathing of the wires and this can cause two wires to cross. I have found that they will eventual chew all the wires and then it causes a short. The good news is a ground fault locator will find the fault. Lightning will blow the solenoids and controller before the field wires melt, the only time I have seen field wires melted from lightening is the point of entry and it blows the wires apart.

Wet_Boots
02-28-2007, 10:31 PM
If the location of the wire run was known, and all four ends of the two wires are disconnected from everything else, one could get a pretty good idea of where to dig by using resistance measurements. (using a digital ohmmeter)

I would agree that lightning damage is more likely to be to solenoids and controllers than wiring, although I have seen cases where the insulation has been fried off the copper. How about mechanical damage? Besides critters, there can be tent stakes, or other items hammered into the ground.

Beartooth
03-01-2007, 01:01 AM
I am trying to track down a locater, one of my distributors has one but it's in another town right now. I probably should bite the bullet and make the purchase however. For now, if I use my multi-meter to check resistance between the two wires, how can I pinpoint the distance the short is from the controllers,or the point of testing? What is the electrical theory behind this?

bicmudpuppy
03-01-2007, 07:35 AM
So, you do or do not have a physical location of all the valves? You do or do not know the in ground wire path? Unfortunately, if you answered not either time, I am inclined to say you still don't have a clue what your talking about. Standard Ohm meter, what do you get at the controller between all wire combinations? If you understand how to use this most basic of tools, you get a wealth of knowledge. Between two station wires, you can get an ohm reading indicating wiring sequence in the field, etc. If your wiring is toasted, you will get an almost dead short between the two or more wires that are crossed. Your casting blame at an act of God for your troubles, but the only thing you have replaced is a controller, unless you haven't given a complete description. Even with 18 gage wire, solenoids should have been damaged long before wiring burned. Now, if your short occured first, possibly due to undersized wiring, this might have caused your controller problem, not lightning. Also, if you do know the location of the valves in the field, have you conducted a voltage check at the valves to measure voltage drop?

SprinklerGuy
03-01-2007, 08:50 AM
Ut oh..............

Beartooth
03-01-2007, 11:42 AM
I can understand how difficult it is to diagnose someone else's problem over the internet with out all of the information. Maybe I have not been clear enough and for that I apologize. I do know the exact location of the valves in question. I do know the wire path. I do not, in fact, know if the lightning strike indeed played a part in the condition we have set before us today. It very well may be that a ground squirrel, rock-chuck, or even something that may have occurred during the installation five years ago is now causing the problem. I am simply trying to troubleshoot a problem with field wiring that did not exist before the lightning strike. The system ran like clock-work. I would agree that my basic skills with electrical theory and electrical principles as they apply to this situation are lacking. I have checked voltages at both solenoids (22.3 and 21.7 respectively). The closest solenoid to the controller is 487' the second solenoid we are talking about is another 42' downstream of the first. The zones in question on this particular controller are zones 7 & 10. I am trying to learn from those of you who have better knowledge than myself and who are willing to help. I do apologize if I have not given enough information.

Wet_Boots
03-01-2007, 12:13 PM
What are your resistance readings between the zones 7 and 10 wires? You'd be measuring at the controller. You'd have a second measurement at the first valve box. Wire ends completely disconnected from the system. You really want a digital ohmmeter (for accuracy of readings) for this, if you want to guess a short location from these measurements.

By the by, using a 18 gauge multiconductor cable for a system this large is a bit suspect, if you want to give yourself a safety cushion. I might make use of a single 14 gauge common wire, and use multiconductor for the zones.

You might also want to check to see if you can read a resistance value between the zone wires and earth ground.

Beartooth
03-01-2007, 12:47 PM
The wire runs probably are a little long for 18 gauge wire and we did run a 14 gauge common. I am going to head out in the snow today and check resistances. I will post my findings later. Thanks!

Dirty Water
03-01-2007, 05:00 PM
You can run 18 Gauge over 1000' as per Rainbird Specifications.

Somehow I doubt they managed to use more than 1000' in any individual run from the timer in 3 acres.

ed2hess
03-01-2007, 06:51 PM
If you got sufficient water pressure let the two stations run together, it is not a problem for the controller!

Beartooth
03-01-2007, 08:39 PM
If you got sufficient water pressure let the two stations run together, it is not a problem for the controller!

Yeah, but it is a problem for the customer!!!

aric43085
03-01-2007, 08:52 PM
with your 521 locator you should be able to find where the nic in the wire is located. I would check in the valve boxes and wire splices first.

ed2hess
03-01-2007, 10:01 PM
with your 521 locator you should be able to find where the nic in the wire is located. I would check in the valve boxes and wire splices first.

I used the 521 for valve locating but ...what do you expect to hear when you get to the nic?

aric43085
03-02-2007, 01:04 AM
The locator will give you a higher tone when you cross over hotspots. Great at finding nics.

PurpHaze
03-02-2007, 08:59 AM
The locator will give you a higher tone when you cross over hotspots. Great at finding nics.

Considering that the 521 works on the "null principle" and actually makes no sound directly over the wire path, how does this work?

SprinklerGuy
03-02-2007, 12:45 PM
If the nick goes directly to ground and the ground is wet...I agree it can find it...

However....the pulsar pulsar pulsar ouch! works much better...