# Zone tripping gfci troubleshoot



## Too_Tall (Mar 15, 2019)

Howdy folks,

Having an issue with one particular zone with my system. It's zone 3 of 12. When running through the program the gfci that's a part of the same circuit that my unit is plugged into will trip.

Some facts,

Only happens in zone 3.
Zone 3 is the closest to where the wires all go into the ground.
It has tripped the gfci anywhere from 7-15ish minutes into that zone.

I've found a buried box close to where the wires enter the ground but have yet to find any valve boxes. The system was installed prior to purchasing the house and I have no record of who put it in.

My next plan is to run an extension cord to run the system on a different circuit breaker plug. (not on the same gfci circuit)

Anything else yall suggest?


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## Too_Tall (Mar 15, 2019)

Nobody huh?... Bummer.


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## g-man (Jun 15, 2017)

You will need to check all your wiring. A GFCI works by detecting a difference in amoerage between the hot and neutral.

Can you swap zone 3 with another zone and see if the problem moves? If it does then the problem is with the wires/solenoid.


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## bhutchinson87 (Jun 25, 2018)

Technically a GFCI actually works by monitoring the amperage of the circuit and making sure whatever current that is going out through the hot is also coming back via the neutral. The GFCI device will trip if the difference is large enough (typically 5mA).

Given that it takes such a long time to trip and only on that one zone a couple things come to mind. The zone 3 valve might be going bad or maybe some excessive erosion into the valve box has created a path to ground.

g-man's test will also prove whether or not something internal to the controller is wrong. Good luck and keep us updated.


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## Too_Tall (Mar 15, 2019)

Thanks for the tips folks. I'll report back.


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## hsvtoolfool (Jul 23, 2018)

Sorry @Too_Tall, but I posted my best guess earlier but in the wrong thread.

I'd follow the advice given by @g-man and swap the bad zone to a different input on the controller. If the issue moves to the new zone, then the valve has a mild short and must be re-wired or replaced. If the error does NOT move to the new zone, then the relay inside the controller for that zone is likely bad.

Givens the symptoms, I suspect the problem is in the controller or the 12V power supply rather than out at the valves. My intuition is that the controller and power supply filter or buffer most shorts at the valves from the GFI faults at the wall plug. At least it would if I designed it. In fact, I'd design the controller to detect excess current draw at the relay inputs and simply disable that zone under serious error conditions.

On the other hand, the actual CAUSE of a damaged relay inside the controller or a weak power supply could be either a shorted valve. So you'd need to find and fix the valve wiring issue first, then fix the controller and power supply as needed. In other words, it could be a two-part problem.

Finally, you could also try replacing the GFI plug itself. I've seen them go bad over time and become overly sensitive. That's a long shot so I wouldn't start there though.


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## Too_Tall (Mar 15, 2019)

Switched the zone 3 wire to a different terminal on the controller and ran the zone again. It still tripped. Means it's isolated to something on that zone and not an issue with the controller or gfci circuit, correct?

Now I have to find out where to go from here. No clue where the valves are. Time to start digging up wires I guess.


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## g-man (Jun 15, 2017)

@Too_Tall that will be the correct assumption now. I would first check the wire connections at the valve for that zone. Look for corrosion.

One way to find out is by the colors. Two color wires at the valve will be connected at the controller. One is the common (all the valves use this and the other one goes to the zone (3). Go outside an look for the right colors.


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## Too_Tall (Mar 15, 2019)

@g-man, @hsvtoolfool ,@bhutchinson87

Gentlemen, thanks for your help thus far. It gave me some good insight on where to go with this issue. That being said after more troubleshooting I'm even more baffled. Each time we ran the test I set the controller for 10 mintues. It typically tripped around 4-6 minutes in.

Found the valve control box for zone 3. Replaced the solenoid and cleaned up all the wire connections in that valve box. 
Still tripped.

That particular box had 1 red power and 3 white common wires. We isolated that zone to just it's common wire. 
Still tripped.

We swapped the red power wire in the main junction box from the first set of pictures where it all comes together. We swapped the zone 4 wire from the control box to the red power wire going to zone 3. Ran "zone 4 control box"/zone 3 in reality.
Still tripped.

This is where it gets odd,
I ran an extension cord from the power supply to another area of the house. This outlet was non GFCI. No issues.

We decided to run the extension cord to another GFCI in the kitchen. Completely different circuit. The kitchen GFCI did fine and the system ran the whole test 10 minutes, but the GFCI in the garage still tripped about 4 minutes into the test.

I'm dumbfounded... Why would the GFCI in the garage trip when the system is being powered from a completely different set of circuits??

Our next step is to replace that GFCI and see where we go from there.


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## g-man (Jun 15, 2017)

I think you should replace the GFCI that is giving you trouble. They can go bad by either not tripping or constantly tripping. We are all supposed to test them monthly by pressing the test button. I'm guilty of not testing mine.


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## bhutchinson87 (Jun 25, 2018)

Definitely sounds like the GFCI device is bad, although I'm surprised since it only tripped on that one zone (unless you didn't run the other zones long enough, but I presumed that wasn't the case).

Technically you are supposed to test monthly like @g-man said, but nobody ever does. That's why all new GFCI receptacles are required to self-test lol

Homeowners are allowed to replace receptacles and switches on their own, but please remember to turn the power off and double check yourself with a voltage pen or voltmeter.


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## hsvtoolfool (Jul 23, 2018)

I think you're down to either the GFI plug, the controller itself, or a weak short to ground in the zone 3 hot wire between the valve solenoid and the controller. First, I'd replace the GFI plug since it's cheap and easy. Second, I'd get a cheap Harbor Freight voltmeter and check the zone 3 hot wire and make sure it's not shorted to ground. Third, I'd replace the controller if nothing else works.


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## Too_Tall (Mar 15, 2019)

The plan is to string a new test wire from the controller to the zone 3 valve above the ground. If it doesn't trip then maybe its the power wire that has a short. If it does still trip were gonna replace the GFCI.

Ive got a Rachio 3 just sitting collecting dust. Wanted to get this issue resolved first so I don't fry it.


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## Too_Tall (Mar 15, 2019)

It was the damn GFCI...

It would have been the first thing I would have replaced had I known. I figured since my issue was only with Zone 3 that surely it was something withing the irrigation system... SOB.

Live and learn. Did 2 10 minutes test runs and no issues. Got the Rachio installed and set up as well. Glad to be done with this issue.


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## g-man (Jun 15, 2017)

:thumbsup:


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