Charger shows E20, external release button or emergency stop is indicated as active, charging cannot start.

Safety first: Emergency stop circuits are safety‑critical. Do not bypass them. Isolate mains before wiring work.

• 1. Check external devices:
  • Locate any emergency stop button or external release switch connected to the charger.
  • Ensure the E‑stop is reset (twist or pull as designed).
• 2. Inspect wiring:
  • Open the charger and find the digital input terminals for E‑stop/release.
  • Check for loose wires, corrosion, or damage.
• 3. Test input behavior:
  • Temporarily disconnect the external switch wiring and install a proper test link as described in the Heidelberg manual.
  • Power up and see if E20 clears (for testing only).
• 4. Replace faulty switch:
  • If the external switch is mechanically stuck or intermittent, replace it with a compatible safety‑rated device.
• 5. Main board input fault:
  • If E20 persists with known‑good wiring and switch, the digital input circuit on the main control board may be defective and require board replacement.