Sprinkler Zone Stoping and Starting Throughout Cycle

[mhalWaters]

Hi all, hoping I can find some help here!

I have a Hunter controller for my irrigation system. There are 6 zones that are programed to run one at a time. The 4th zone will suddenly lose pressure and stop mid cycle, the heads drop down, then start back up seconds later - and then the process repeats every 10-40 seconds or so. It happens when the programmed cycle is running and when I manually run just that zone. If its worth noting - no other zones have had any issues.

When this happens, I can hear a vibration/slight bang noise if I'm inside the house. I don't know if its from the sudden stopping of the water flow or a noise coming from the back flow preventer just outside the house.

Has anyone had any experience with this type of issue? I'm hoping to rule out any troubleshooting steps before needing to find someone to service it. Thank you for any help or ideas folks can offer!

 

[WorthFlorida]

What is Hunter controller model number? Hunter fails usually two ways, 1) the controller board lans burns out or 2) the plug in modules go bad. If you remove the board from the housing and look on the back side of the main control board, look for burned lans. Some call then conductive traces. They are the copper looking conductors between components.

First check that there is 24v ac. No load as high as 27-28v, with load as low as 18v. Depending on your model, if there are any expansion modules, remove them. Usually the first three or four zones are built in. Some are all built in.

Disconnect all zone wires except zone one and the common wire. Start the program and if the zone 1 works as expected, add the second zone and test again. Do this until the problem occurs. If it starts on the first zone, disconnect the zone wire and connect zone two wire to the #2 zone, etc. If you find one zone causing the problem, move that zone wire to another zone to prove if the problem is at the solenoid or the controller.

A shorted solenoid can do crazy things since the 24 voltage will drop but some Hunter models will display zone should the solenoid have a short and deactivate that zone.

The bang noise is the solenoid rapidly closing. Between zones the controller will start to open the next zone before closing off the current zone. This prevents what you are hearing, rapid shut down of water flow.

 

[Sponsor]

 

[Jeff H Young]

sounds like the solenoid is bad. What a Dummy like me would do is forget all that electrical stuff and swap the wires with a zone that works. could be a connection but thats how id test it

 

[mhalWaters]

Thank you! I tried swapping the wires with another zone and running a brief cycle, confirmed its still happening. My next step is going to be trying to find the control box for that zone, so I can try swapping in a new solenoid. If I borrow a metal detector do you think that would help me find the box? I know the wire tracing equipment is expensive...

I tried listening for the solenoid "click" while the system was running / turning off and I think I could hear the general area it is located in

 

[WorthFlorida]

Metal detector will not find the zone valve unless it is old and made of pot metal. Most are all plastic. I bought a cheap tracer tool off of ebay or amazon and it doesn't work very well. If you have a pitch fork, poke the ground, lightly. Either all zone valves are next to one another or spread out over the lot. If you know where the first sprinkler is for that zone a good chance it is nearby.

The thump you heard is very common when the zone valve shuts downs and you can get an idea where it is if you can hear it. Usually the sound travels down the pipe. When you do find the zone valve, turn the solenoid a 1/4 turn CCW and it should open the valve. Possible the wire connection to the solenoid is bad from corrosion or a something chewed the wire.

 

[Jeff H Young]

youve diagnosed and what is problem? wire, control box, or solenoid? replace the bad one

 

[mhalWaters]

So I found the valve box for that zone! I replaced the solenoid and diaphragm, and used water resistant wire connectors (the wire connectors that were in there were standard non-water resistant).

The zone ran fine during the cycle, but did stop / start 2 times in the last minute of the cycle, is that the system relieving the water pressure at the end of the cycle, or still hinting at some other issue?

 

[mhalWaters]

youve diagnosed and what is problem? wire, control box, or solenoid? replace the bad one

I think it was the solenoid, but I also replaced the diaphragm while I was at it

 

[WorthFlorida]

So I found the valve box for that zone! I replaced the solenoid and diaphragm, and used water resistant wire connectors (the wire connectors that were in there were standard non-water resistant).

The zone ran fine during the cycle, but did stop / start 2 times in the last minute of the cycle, is that the system relieving the water pressure at the end of the cycle, or still hinting at some other issue?

Great! The end part could be the controller. The zone change is only about a five second or less window, however the replacements did make a big difference. Just let it alone for now. It's only water dumping on the ground. A slight possibility is a stone is inside the pipe moving around.
While the zone is running, just disconnect the one zone wire and see how the zone shuts down. Another is with a volt meter on the trouble zone, let the program run and watch the voltage to the zone. It should just drop to zero. If it doesn't check another zone.

 

[mhalWaters]

Thank you all so much for the help - This has been bugging me since last summer, so I'm glad to finally have a meaningful fix in place!
@WorthFlorida I'll try out those tests. The controller model is a Hunter IC-600, which I think is an older model - if the issues are stemming from the controller, maybe its time for a new one?

 

[Jeff H Young]

Shouldnt be any doubt where the problem is after diagnosing , If you arent using all the zones on controller fill an empty spot.
Ive gotten good responce with rainbird. I assume you would have to call hunter to attempt repair of unit , they can tell you if there are any parts available. 2, 3 and 5 yr warrantys on various controlers by hunter

 

[WorthFlorida]

That Hunter model was probably their biggest seller. If you want to go new, I do like Rainbird as Jeff recomended. They are more reliable and easy to program. I have the ESP-ME3 with the WiFi module. It took awhile to find everything on the WiFi app. You can program, run a program or individual zones with the panel switch turned off.