Display shows “Err 09” and unit regenerates too frequently or not at all based on usage

Safety: No internal electrical work is required for programming, but avoid opening the valve while pressurized.

Steps:

• 1. Verify water hardness: Test raw water hardness with a reliable test kit or obtain data from your Sterling dealer.
• 2. Check programming: Enter the programming mode on the Sterling control (refer to manual). Confirm hardness, capacity, reserve, and regeneration type (metered/time clock) are set correctly.
• 3. Reset to factory defaults: If settings appear corrupted, perform a factory reset (if available) and re-enter all parameters.
• 4. Confirm flow meter operation: Run water and ensure the display shows flow and counts down remaining capacity. If not, address flow meter issues (see Err 03/08).
• 5. Replace board if needed: If programming will not save or changes randomly, the main control board may be defective and should be replaced.