Fixing a Rain Bird ESP-6 That Freezes at 12:14 AM

Symptom: Controller Locks Up at Same Time Weekly

A Rain Bird ESP-6 that consistently freezes at 12:14 AM on Tuesdays suggests a microprocessor or memory issue, often triggered by a failing backup battery.

Required Battery Type

This model requires a 9 V rechargeable NiCd battery—not an alkaline. An alkaline battery can leak or fail to hold charge, causing erratic behavior.

Reset Procedure

1. Remove the backup battery.
2. Disconnect AC power for 60 seconds.
3. Reconnect power, fully reprogram the controller.
4. Install a fresh 9 V NiCd rechargeable battery.

If the Problem Persists

The microprocessor or clock circuit is likely damaged. Given the age (3+ years) and low cost of modern replacements (e.g., Rain Bird ESP-TM2, Hunter Pro-C), replacing the controller is more economical than repair.

Prevention

Replace the NiCd backup battery every 2–3 years. Mark the installation date on the battery with a marker.