Display shows Err6 and time-of-day or regeneration schedule will not hold settings

Safety first: Disconnect power before removing the control panel or board cover.

Step-by-step checks:

• 1. Verify stable power: Confirm the Marlo softener is plugged into a properly grounded outlet and that there are no frequent power interruptions. Avoid using switched outlets or power strips that are turned off regularly.
• 2. Reset control: Perform a soft reset according to the Marlo manual (often by holding specific buttons). Re-enter the time, hardness, and regeneration settings. Monitor whether Err6 reappears after a power cycle.
• 3. Inspect control board: Remove the control cover and visually inspect the board for corrosion, burnt components, or a leaking backup capacitor/battery (if present). Do not touch components with wet hands.
• 4. Check low-voltage transformer: Verify that the transformer output matches the Marlo specification (typically 24 VAC). Low or fluctuating voltage can cause memory errors.

When to replace parts: If settings are repeatedly lost and Err6 persists, the Marlo control board assembly likely needs replacement. If the transformer output is unstable, replace the Marlo low-voltage transformer as well.