Troubleshooting Hunter EC and XC Controller Error Messages

Experiencing erratic error messages on multiple Hunter controllers—both EC and XC models—can be frustrating, especially when field wiring checks out perfectly. In one case, three EC controllers were installed in a three-unit development; two began displaying "ERR" messages (not "P ERR"). Bench testing one unit with three solenoids wired directly revealed it operated correctly 90% of the time, but occasionally showed an error right before the valve opened, with the display reverting to the time instead of run time.

A separate XC controller, installed to replace an EC, held station 2 open permanently after a week of normal operation. Swapping the K-Rain solenoid didn't help, but connecting a Rain Master controller resolved the issue. Bench testing the XC showed no faults.

Likely Wiring Issue

Since different controllers exhibit similar problems, the root cause likely lies in the valve wiring rather than the controllers themselves. A short or poor connection in the common wire is a frequent culprit. This type of fault can cause intermittent errors and unexpected valve behavior across multiple controllers.

Recommended Steps

• Thoroughly inspect the common wire for damage, corrosion, or loose splices.
• Contact Hunter Industries technical support—they're typically responsive and can provide model-specific guidance.
• Consider isolating each valve circuit to pinpoint the problematic zone.

Don't assume a "bad batch" of controllers; systematic wiring diagnosis usually reveals the true issue.