Wiring Pump Start Relay and Valves to New Orbit 6-Zone Controller

After adding two zones and replacing a Rain Bird ESP-4 with an Orbit 6-zone outdoor controller, the pump won't start—likely a wiring issue at the pump start relay terminals.

Correct Relay Wiring

The pump start relay needs two wires from the controller:

• One to MV / PUMP START terminal
• One to C (COMMON) terminal

Critical: The valve common wire AND the relay common wire both connect to the same C terminal. You may have two (or more) wires under one terminal screw—that's correct.

Troubleshooting Steps

1. Verify 22–26 VAC at MV terminal when any zone runs (meter: C to MV).
2. If no voltage → controller issue (check programming: pump start enabled?).
3. If voltage present → check at relay coil terminals. No voltage = broken wire.
4. Test relay: jumper MV to C at controller → relay should click, pump run.

Common Mistakes

• Relay wired to station terminal instead of MV
• Relay common not connected to controller C
• Bad relay (test with jumper)
• Controller pump start feature disabled in settings

Methodically check voltage at each point. Trial-and-error wiring wastes hours.