Safety first: Unplug the unit and remove all water from tanks before opening the housing.

Inspect base tray: Remove the lower cover to access the leak tray and leak sensor (often a pair of metal contacts or a small module). Dry any water with towels.
Identify leak source: Fill the fresh water tank with clean water, reinstall, and observe the internal hoses and pump area (with power still disconnected). Look for drips from solution hoses, hose connectors, or the pump housing.
Tighten or replace fittings: Tighten hose clamps, replace cracked hoses, and reseat quick-connect fittings as needed.
Dry and reset sensor: Thoroughly dry the leak sensor and surrounding area. Some sensors may need a short time to reset after drying.
Test carefully: Reassemble, refill, and test for leaks while monitoring the base. If E13 returns without visible leaks, the leak sensor itself may be faulty.

Display shows E13; unit will not start due to internal leak detection.

Possible Causes