Zerowatt SpazioTop / LadyPiù / Optima Washing Machine: Anti-flood safety trigger E04; electronic controller detects excessive water column level or floor leak sensor switch closure.
On Zerowatt washing machines powered by integrated GIAS Invensys circuit architecture, electronic commutator drive motor, and mechanical pressure calibration: Leaking tub gasket, blocked pressure switch air bell tube, or triac short energizing inlet valve continuously.
Isolate water supply. Inspect base pan for leakage. Detach pressure switch hose and clear chamber sludge. Check valve triac voltage with a multimeter (230V AC). Turn dial to Off, hold Start/Pause and Spin speed buttons together for 5 seconds until the status lamps pulse, then power cycle.
