lawn sprinkler electrical question

[Burt]

I have one of the six zones on my lawn sprinkler system that is not working. Three of the solenoid valves are next to each other over 100 feet from the controller box. They share a common ground wire.


I have 25 volts at the controller box. If I disconnect the wires at the solenoid, I get 25 volts on two of the lines and the solenoid valve works, but only 6 volts on the last solenoid on the common ground line. It doesn't work What would cause this and how do I trouble shoot it?

 

[FSully1]

Is the controller putting out 24-26 volts on that zone?

 

[Burt]

but the line with 6 volts is not connected to its solenoid when I test it. could one of the other solenoids be bad and affect the last one?

 

[FSully1]

Need to find why your only getting 6 volts to that zone. Test voltage for that zone at the controller.....one probe on common terminal the other on "zone #" you should read 24+volts

 

[Burt]

Originally Posted by FSully1
Need to find why your only getting 6 volts to that zone. Test voltage for that zone at the controller.....one probe on common terminal the other on "zone #" you should read 24+volts


Yep. Done that and got 24v at controller on all 6 zones. Even switched hot wires at the controller and good circuit stayed good and vice versa. My guess is some sort of fault or one of the upstream solenoids is leaking electricity backwards through the common ground if that makes sense.

 

[mk378]

Ohm test the solenoids at the box. They should all measure the same.

Then hook up all the wires in the valve box, go back to the controller and disconnect the wires there. Ohm test the solenoids again through the wiring. They should again be the same, but maybe an ohm or two more because of the wire.

An easy test of the controller is to swap the wire of the zone that doesn't work onto a controller output that you know does work. When you turn on that zone, the valve that didn't work before should open.

 

[flanso]

If FSully1's suggested test shows 24 volts for that zone at the controller, try switching the wires between the "bad" zone solenoid and a working zone solenoid. If the non-working zone stays the same, its solenoid is bad. If the bad zone moves, you have a bad conductor back to the controller, either the ground or the 24 volt one. If it is the solenoid, I think Rain Bird still sells replacement coils for their solenoids. Although wire nuts for irrigation are filled with dielectric goo, the wires sometimes corrode. You might want to check the wire nuts before going through the ordeal of running a new wire.

 

[FSully1]

Originally Posted by flanso
If FSully1's suggested test shows 24 volts for that zone at the controller, try switching the wires between the "bad" zone solenoid and a working zone solenoid. If the non-working zone stays the same, its solenoid is bad. If the bad zone moves, you have a bad conductor back to the controller, either the ground or the 24 volt one. If it is the solenoid, I think Rain Bird still sells replacement coils for their solenoids. Although wire nuts for irrigation are filled with dielectric goo, the wires sometimes corrode. You might want to check the wire nuts before going through the ordeal of running a new wire.


bad solenoid / wiring issue.

 

[Kode]

Some ground fault draining. "One wire is all it takes".

 

[Burt]

Post Mortem: I wired above ground extensions from the good valve to the bad and it worked. It appears the ground wire to the bad valve is cut and hot wire is leaking voltage. It appears I need to replace both wires which will take a little digging.