E3 on the ASKO WM76S indicates a filling problem. Check the water supply, inlet, and drain placement according to the W3096RW manual before trying again.
From the faucet to the water level
The manufacturer documentation covers the faucet, inlet screen, hose, and drain height. First check whether water is being supplied and whether a valve was left closed. Look at the hose for any sign of crushing or deformation.
If water enters but is not retained, note whether it is draining out at the same time. Compare the height and connection with the installation section: a setup that promotes siphoning is not fixed by resetting the panel.
Accessible screen and recovery
When the manual allows cleaning the inlet, shut off the water, prepare the equipment, and disconnect only the specified fitting. Reinstall the screen and gasket, and check for leaks. The guide to inlet filters expands on the preparation.
The WM76S manual says to continue by confirming the panel after checking the conditions. If E3 returns, request service with the model and a note about the filling issue. The allowable pressures are given in the manual; do not apply its limits to other ASKO generations.
Distinguish restoring the supply from clearing the message: only the first fixes a water outage.