Wiring question

Keegan

LawnSite Senior Member
Location
CT
I work at a school and one of the fields just developed a problem with the irrigation system. It has worked fine since it was installed about 10 years ago. Just recently I turned Ione zone on and two zones were going off at the same time. The zones are on opposite sides. How does this happen? Could someone have messed with the wires in the control box?

TYIA
 

1idejim

LawnSite Fanatic
I work at a school and one of the fields just developed a problem with the irrigation system. It has worked fine since it was installed about 10 years ago. Just recently I turned Ione zone on and two zones were going off at the same time. The zones are on opposite sides. How does this happen? Could someone have messed with the wires in the control box?

TYIA
You’ve probably got a direct short between the zone wires for said valves.

Pull one of the affected zone wires from the terminal strip and run the other affected zone. Both zones will run, reattach the lose wire and do the same on the other affected zone, both zones will run.

You can troubleshoot this situation with a digital multimeter using resistance measurements.

1) measure between the common port and each zone terminal port.

2) compare your results, the valves running together will give you approximately one half the resistance value of each of the valves working alone.

3) if this is the case, remove both of the affected zone wires from the terminal strip and measure each zone wire to the common and then between the isolated valve wires.

4) for example let’s use 30 ohms as the average for the solenoid/zone value. Between the common and affected zones you should see a value of 12 - 18 ohms.

Measuring between affected zone wires you may expect to read 0 - 5 ohms OR 24 - 36 ohms. Both indicate a direct short.

5) perform a short to earth measurement at both ends of the wire path and the lowest value tells you which end is closest to the short.

The method I just described takes less time to perform than it did for me to type. Best of luck :)
 

Outlawn

LawnSite Bronze Member
Location
San Angelo, TX
Is it only with that other zone or does it turn on with any zone that’s on? Could just be a bad diaphragm or even manually left on if there is a master valve.

Otherwise ^ what Jim said!
 

1idejim

LawnSite Fanatic
  • Is it only with that other zone or does it turn on with any zone that’s on? Could just be a bad diaphragm or even manually left on if there is a master valve.
Otherwise ^ what Jim said!
When you have multiple zones activating consistently with all zones, for example, (1-2, 2-3, 2-4, 2-5) number 2 is touching the common somewhere.

I did a job a few years back where a Sheetrock nail was the culprit.
,
Wires left the clock in the garage, traveling through the wall to a wine cellar and into a junction box just outside the wine cellar.

When any zone was activated, 2 other zones came on. I isolated the 2 of the constants at the junction box and fired up the system, the isolated zones still came on.

That narrowed the search to the wall where we found a Sheetrock nail which pierced the insulation common and 2 zone wires.
 

1idejim

LawnSite Fanatic
When you have multiple zones activating consistently with all zones, for example, (1-2, 2-3, 2-4, 2-5) number 2 is touching the common somewhere.

I did a job a few years back where a Sheetrock nail was the culprit.
,
Wires left the clock in the garage, traveling through the wall to a wine cellar and into a junction box just outside the wine cellar.

When any zone was activated, 2 other zones came on. I isolated the 2 of the constants at the junction box and fired up the system, the isolated zones did not come on.

That narrowed the search to the wall where we found a Sheetrock nail which pierced the insulation common and 2 zone wires.
Caught my own mistake!

I do have the advantage of being the only one reading my posts :laugh::laugh::laugh:
 

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