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Irrigation/Toro Irrigation System Partial Failure


Irrigation box
Irrigation box  

control box
control box  

I have a Toro six zone irrigation system that feeds off a small lake.  After the system was de-winterized, I immediately had a problem with 3 zones.  Initially, two would not activate (zones 3 and 4...which are a pair in the control box) but they would operate if I manually open the valve located in an irrigation box in my backyard and then turn the system to RUN at the control box.

I also had a 3rd zone (zone 5) which initially did not work automatically but did work if I manually opened the valve, now it won't work at all (even if I open the valve and then run the zone via the control box).  And now, zone 4 is behaving like zone 5.  It won't operate manually or automatically any longer.  This occurred after I worked on all the wires but the wires are in good shape, tied together and capped.

The wires in the irrigation box were connected via DryConn wire connectors which is not as good as a grease cap which I purchased to put on after I fix this thing. The irrigation box is in the ground and will flood in a strong storm.

What I have done and discovered:
1. I clipped all the wires, stripped a new 1/2 inch of exposed wire and re-connected.  That did not help.

2. I swapped the zone 5 and zone 6 wires on the control box then ran the system.  When the former zone 5 wire was plugged into the zone 6 slot, it did not work.  However, in that same setup, zone 6 turned on when it was plugged into the zone 5 so I guess it is not a problem at the box (?)

3. I tested the voltage at the box by pulling out each colored wire and touching a voltage meter to it and then connecting the other lead to the white wire seen in the picture (I thought that was the common wire).  There was no voltage to any of the zones.  But if I touched the red wire instead of the white, all zones registered 24 volts.  

4. When zones 1 and 2 are turned on, there is no solenoid buzz in the irrigation box; when zone 3 turns on there is a strong buzzing, zone 4 a faint buzzing from the same solenoid as #3, zone 5 a very strong buzzing (different solenoid) and zone 6 no buzzing

5. I replaced the solenoid for zone 5/6.  No buzzing but still no water flow to zone 5.  Zone 6 operates as it did with the old solenoid.  So no change whatsoever.

6. The solenoid for zones 3 and 4 appear to be part of the valve casing.  The solenoid for zones 1 and 2 can't be seen but I think it is going to be part of the valve but at the moment those zones operate fine.

I was going to try to go through this using the tester in the second link but have not done this yet:

Fyi, the system is 10+ years old.  It came with the house I purchased in August.  Also, after de-winterizing the valves in the irrigation box were in the closed position.  To manually operate the system I opened the valves and left them open for a week.  Don't know if that was a no-no but I only did that AFTER having the problem with the zones.  Lastly, the pump is working fine in all cases.  

Thanks for any ideas you can provide to fix these 3 zones.  And, curious, can a solenoid be bad for just one of the two zones it controls?  Zone 5 won't operate but zone six runs fine off the same solenoid. Is that telling me something?  Also, zone 3 operates if I manually open the valve and then run the system but zone 4 won't work manually or automatically.  

Service people here are slammed.  Wait times are 3 weeks, so just hoping to get this solved on my own but I am going nuts trying to figure this out.


Hey Don, It sounds like you have some bad diaphragms. With the water off, if you take the solenoid off, turn the valve # on by the controller you want to check, and the plunger inside the solenoid will get sucked up inside the solenoid, this will tell you if the solenoid, wires, and controller are working properly. If the solenoid is working properly, then the next thing that is wrong would be the diaphragm. Go to and this website will show you how to rebuild a valve. If you open the bleed screw on top of the valve, and it does not work, then the diaphragm is completely broken off and is stuck in the bottom of the valve body. Good luck and have a great day.


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Jim Schaefer


Any question regarding sprinking systems,installation,repair, and trouble shooting.


I have been installing and repairing sprinkling systems since I was 15 years old. Have owned my own sprinkler system contracting business for over 26 years. It is basically the only job I've ever done, except for being a paper boy when I was young.

High School diploma and 3 years college credits.

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