E18 displayed: high temperature detected at the control head.

Safety: Unplug the unit before inspecting the control housing.

• 1. Check environment: Ensure the RainSoft softener is not installed directly next to a furnace, boiler flue, or in direct sunlight. Provide ventilation and clearance per the installation manual.
• 2. Inspect temperature sensor: Locate the thermal sensor on or near the control board. Ensure it is firmly attached and not damaged.
• 3. Clean vents: Remove dust and debris from any ventilation slots in the control housing.
• 4. Measure temperature: Use an infrared thermometer to confirm actual temperature at the control. If normal but E18 persists, the sensor or board is likely faulty.

Next step: Replace the temperature sensor or the entire control board if the sensor is integrated.