The H51 error is one of the most common issues. It occurs when a washer fails to drain properly due to a clog in the outlet hose or excessive load. If you see the error on the LCD screen, open a small door in the bottom left part of the washer using a knife or another flat and sharp object. Pull the tube out of the clip and drain water from the filter area. Use a bucket. Make sure the machine is in the spin-only mode. To launch the mode, press the Spin button until no spin is reached. Continue to use this mode until water stops running into the bucket. Then switch off the machine and disconnect it from the mains. Open the filter housing. Be prepared to deal with some water coming out, so do not put away the bucket. Turn the filter counter-clockwise until it can be extracted from the housing. Clean it, remove debris or foreign objects, if any. Put it back into the filter holder, close the housing and plug the device back in. You can reduce the load a little. If the error appears again, unplug the machine, wait 60 seconds, plug it back in and launch a cycle.