Chemical dosing error; control detects out-of-range detergent or rinse aid usage and shows E20.

Safety first: Disconnect power and wear chemical-resistant gloves and eye protection.

• Inspect pickup tubes: Ensure detergent and rinse aid pickup tubes are fully submerged and not blocked or cracked.
• Bleed air from lines: Use the prime function on the chemical controller or Insinger control to purge air until a steady stream of chemical flows.
• Check flow meter (if present): Inspect the chemical flow meter for blockages or damage. Replace if it does not register flow.
• Recalibrate dosing: Follow Insinger or chemical supplier instructions to set correct pump run times or flow rates.