Orbit Controller Replacement: Zone 2 Works on Old Rain Bird But Not New Orbit

After upgrading from Rain Bird to Orbit (tried two different Orbit models), zone 2 refuses to work on either new controller. Zone 1 works everywhere. The original Rain Bird operates both zones perfectly. Wires were clearly marked: white-common, blue-zone1, green-zone2.

Voltage Testing Is Essential

The fact that zone 2 works on the Rain Bird but not Orbit controllers suggests a voltage or current difference. Newer controllers may output slightly less voltage, exposing a marginal wiring or solenoid issue.

Diagnostic Sequence

1. Test controller output - Measure VAC between Common and Zone 2 terminal on new controller (should be 22-26 VAC)
2. If voltage is good at controller - Test at zone 2 solenoid wires (disconnected from solenoid)
3. If voltage drops at valve - Wiring issue: damaged but not severed wire, corrosion, or poor splice
4. If voltage is good at valve - Solenoid or diaphragm issue

Most Likely Causes

• Zone 2 hot wire (green) has high resistance from partial damage
• Zone 2 solenoid is weak but functional with Rain Bird's slightly higher output
• Common wire connection degraded at zone 2 valve box

Practical Fix

Replace the zone 2 solenoid first ($15-20). If that fails, run a new wire from controller to valve 2, or hire a pro to locate and repair the underground break.