How can I fix a Zanussi Aquasave Des 959?

AL5 is almost certainly caused by a float switch being triggered in a shallow water collecter tray under the machine. To verify this, tip the machine a bit which will cause water to run over the floor. Once the water level has gone down, the machine will have re-set itself after switching it back on. You must have a leak somewhere, probably a hose connection or a split hose.

Andy Draper
June 2008