Sprinkler Notes

...though I have owned a number of brands over the years. Operationally, a sprinkler valve consists of three controls. I add comments about them here:

• solenoid—automated part, but also manual shut-off
  • The default state is screwed in all the way (clockwise until it stops).
  • Never, never tighten the solenoid with any kind of wrench.
  • Unscrewing slightly the solenoid will turn on the valve.
• flow-control valve (if you have one, it's usually shaped like a cross)
  • The default state is wide open (counterclockwise until it stops)
  • Close a bit only if too much water is overwhelming the sprinklers controlled. (This is kind of an advanced calibration.)
• manual bleed screw (more rarely called a manual decompression valve)
  • The default state is completely shut (clockwise until it stops)
  • Open to flush out tiny crud that's holding back the valve from shutting off. (See details in section below on this page.)
  • Never unscrew completely except to clean and then only with system water turned off (or it may get away from you—causing you to lose the screw and spraying water all over everywhere while you run to turn off your water).

I have owned valves that didn't possess a flow-control valve. I can't remember how flow-control was regulated, but I'm pretty certain that less expensive valves simply come wide-open with no adjustability.

This is entirely a problem at the valve. There's a easy solution to it, if it works, or another, more involved solution. You should try the easy one first.

The easy solution

Turn bleed screw counterclockwise a bit to flush the valve (don't unscrew it all the way—see warning higher up on this page). This should flush out tiny debris holding the valve open so that the zone doesn't continue running when turned off (at the controller).

If this doesn't resolve the issue, it's probably the diaphragm that needs to be replaced or, at least, cleaned. Here's how to replace it.

The harder solution—replacing the diaphragm

1. Shut off water supply.
2. Remove solenoid.
3. Remove the ring of screws holding the bonnet to the top of the valve body.
4. Replace diaphragm et al. with what comes in a diaphragm-replacement kit, usually consisting of:
   • diaphragm
   • 6 screws
   • a spring
   • a solenoid filter
5. Replace solenoid filter, a different-colored part at the business end of the solenoid.
6. Replace diaphragm (mind the orientation: it fits only one way). Fit it to the valve body (the bonnet is off, right?)
7. Position the new diaphragm spring on the diaphragm.
8. Replace the bonnet carefully over the new diaphragm (mind the spring).
9. Reinstall (or replace) the 6 screws.
10. Reinstall the solenoid until hand-tight. (Don't tighten with a wrench.)
11. Turn water supply back on. There are ways to test to see if you've fixed the problem:
    1. Unscrew the solenoid slightly until the zone begins to water. Then screw it back in. The zone should stop watering.
    2. Run the zone manually from the controller. Observe that the zone stops watering.
    3. Allow the controller to run in automatic mode and pay attention that the zone whose valve you just fixed stops watering.