Display shows E5 and unit remains in service mode without softening properly

Safety first: Unplug the power adapter before opening the control head. Water can remain on; no need to bypass for programming-only work.

Steps to troubleshoot E5 (programming):

• 1. Power reset: Unplug the unit for 5 minutes, then plug back in. If E5 clears, re-enter your Aquasana softener settings (hardness, regeneration time, etc.) according to the installation manual.
• 2. Verify settings: Enter the programming mode and confirm that water hardness, regeneration frequency, and time of day are set correctly for your Aquasana model.
• 3. Check power supply: Ensure the Aquasana power adapter is the correct voltage and not damaged. Avoid using long extension cords or outlets shared with heavy appliances.
• 4. Surge protection: If E5 appeared after a storm or outage, consider adding a surge protector to the outlet.
• 5. If E5 returns repeatedly: The control board’s memory may be failing. Replace the electronic control board / control head assembly. This is typically a technician-level repair.