Control panel displays E01 and the hot tub will not start heating or run filtration.

Safety first: Unplug the Avenli spa from the mains before opening any access panels or handling water connections.

• Check water level: Ensure the water level is between the MIN and MAX marks on the spa wall. Low water can trigger flow protection.
• Clean or replace the filter:
  • Remove the filter cartridge from the filter housing inside the spa.
  • Rinse thoroughly from the inside out with a garden hose.
  • If the pleats are collapsed, slimy, or discolored, replace with a compatible Avenli filter cartridge.
• Bleed air from the system:
  • With the spa filled, briefly loosen the filter housing or a hose connection at the highest point to let trapped air escape, then retighten.
  • Plug the spa back in and run the filtration mode for several minutes.
• Inspect circulation pump:
  • Listen for the pump when filtration is commanded ON.
  • If it hums but no water moves, the circulation pump impeller may be jammed. Disconnect power, remove the pump access cover, and check for debris at the impeller.
  • If the pump is silent and does not attempt to start, the circulation pump assembly may have failed and should be replaced.
• Reset the spa: After cleaning and bleeding, unplug for 5 minutes, plug back in, and restart. If E01 returns immediately, further diagnosis of the flow sensor or pump wiring is required.