Hunter EC 'NO AC' Error After Siding Work: Transformer or Controller Fault?

Hunter EC Shows "NO AC" After Re‑Siding; Wiring Questions

The Hunter EC is notorious for false "NO AC" alerts. First, verify the transformer output.

Tests

1. Check 120 VAC wiring to transformer: black‑to‑black, white‑to‑white, green to ground.
2. Remove lower front panel, measure voltage at the two transformer output wires on the terminal strip. Should be 24–26 VAC.
3. If voltage is good, the controller is bad—replace with a Rain Bird ESP or Irritrol Rain Dial (more reliable).
4. If voltage is low/zero, replace the transformer.

The turquoise wire is likely a ground; it should connect to the green wire or the metal cabinet.