Zone 6 Also Activates Zone 5 – Valve Not Closing Fully

Symptom: Zone 5 Runs When Zone 6 Is Active

On an 8-zone Rain Bird system, zone 5 operates alone correctly, but when zone 6 runs, zone 5 also comes on. The goal is to separate them for better pressure on zone 6.

Likely Cause: Zone 5 Valve Not Sealing

Since zone 5 works independently, the wiring is likely correct. The issue is that the zone 5 valve isn't closing completely when it should be off. A small leak past the diaphragm makes it appear as if zone 5 is running when zone 6 pressurizes the mainline.

Quick Fix Attempt

1. Locate the zone 5 valve.
2. Tighten the solenoid (snug, not overtight) and the manual bleed knob.
3. Test zone 6 again.

If the problem persists, the valve's diaphragm or seat may be damaged, requiring valve bonnet replacement.