Fixing a Hydrotech 4000 Indexing Valve That Skips a Zone

One zone on a Hydrotech 4000 indexing valve skips intermittently—most of the time it doesn't run.

Troubleshooting Steps

1. Clean the controller panel: Use canned air and a soft brush to remove dust from the circuit board.
2. Check wiring: Ensure all wire connections are tight at both the controller and the valve.
3. Test by moving the wire: Connect the wire for the problematic station to a spare/unused terminal on the controller. If the zone runs reliably on the new terminal, the controller’s original terminal is faulty.

If the valve itself is mechanical (indexing valve), debris in the valve body or a worn indexing mechanism could also cause skipping. Disassembly and cleaning may be required.