I have an Orbit 8 station irrigation controller (although I have only 4 stations/zones).

One of the valves started leaking. Here is the setup and I have labeled stations 1 2 3 4. Zone 3 is leaking.



Now normally I would just go and replace that particular valve and be done with it, but something puzzles me.

When the controller activates the valves and turn on zone 1, then off, then zone 2, then off, then zone 3, then off, this is when zone 3 leaks, when it moves to zone 4, zone 3 continues to leak. When the entire system goes off, zone 3 still leak.

I can't quite determine where the leak is coming from, because it is leaking quite a bit, and the entire valve is wet. I don't think it is at any of the threaded connections.

Based on that, my initial conclusion is the solenoid is faulty and once zone 3 is opened, it doesn't get turned off 100%. But this doesn't explain it, because if the solenoid for zone 3 is not closing, it should be seeping water slowly out of the sprinkler heads, but not leaking out of the valve for zone 3. Right? So there must be a crack or a bad connection?

So now in order to stop the leak temporarily, I turned off the shutoff ball valve to the left. That stopped the leak. So I used some paper towel to dry off the valve, so that I can see better where the leak may be coming from.

Once dried, I turned the ball valve back on, expecting the leak to return. But it didn't. No leak. I turned the ball valve back off and on again, no leak.

Waited a few more minutes, nothing. Valve is dry.

Now I manually activated the controller to cycle through the zones, zone 1...2...3...then zone 3 ends but the valve for zone 3 leaks, and will keep leaking until I turn the ball valve off. But turning the ball valve back on does NOT bring back the leak.

WHY? What am I missing that I am not connecting the dots.

The zone valve's 'internals' are not operating properly.

This is quite common with PLASTIC spring loaded 'semipiloted' valves

Simply replace the valve and be done with it.

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"Measure Twice & Cut Once" - Retired U.A. Local 1 & 638



Edited 1 times.

So are you saying the leak happens due to back pressure?

the valve has some internal open/close mechanism that doesn't work anymore, and is still open or partially opened, but since the sprinkler heads have retracted, there is a pressure buildup not enough to pop open sprinkler heads but enough to create a leak from the valve body.

When the ball valve is shut off though, the leak stopped which is expected. But when the ball valve is turned back on, no leak, that's what is confusing me, I would expect it to leak again, and I was going to turn on the ball valve just a little to create a very tiny leak so I can tell where it's coming from. But the ball valve off and on didn't bring back the leak. Unless, when I shut if off some spring closed off inside the valve body.

exactly ...... some 'spring' or diaphragm inside the valve body



there are MANY different 'piloted' valve designs




as a side point: ? ever wonder WHY some dishwashers have MINIMUM operating water pressures when they are 'spray pump' operated ....... similar type of inlet valve ?

==============================================

"Measure Twice & Cut Once" - Retired U.A. Local 1 & 638



Edited 1 times.

Sum, what's the elevation of the sprinklers for zone 3, in relation to the valve? I know you stated this just started happening, but is it possible to be backflow? Valves are suppose to be at least 6" higher than the highest outlet.

steve, the elevation of the sprinklers varies. Some of them are at grade level so will be lower than the zone 3 valve, but there are a few at the corners that are raised higher with a 12" riser to get them to spray farther.

a vacuum breaker must be 6" above the highest 'outlet', not the 'control valve' which often is in a box below grade

==============================================

"Measure Twice & Cut Once" - Retired U.A. Local 1 & 638

Once the zone is turned off and the solenoid releases, the spring in the valve isn't strong enough to fully close the valve against the incoming water pressure. Once you cut off the water, the spring doesn't have to fight that resistance and fully closes the valve. Once it's closed, it stays seated when you restore water pressure.

As bern says, just replace the valve and be done with it.