Here's the correct answer for our Nautilus 1 door two tray dishwasher:
The F1 display and continuous beeping means that the flood switch is activated. It could be activated because of water (just being damp won't do it). Or it could be activated because a naughty mouse built its nest underneath the piece of coolite foam that activates the switch (which is what happened to us).
1) Unplug the dishwasher from the power point
2) Remove the cover plate under the door - there's a vertical screw on each side hidden from view. Don't remove the centre screw as it's just connected to an earthwire lug.
3) Remove the earth wires from the two lugs
4) Remove the second plate by lifting it up and pulling forwards. It's got the wiring diagram on the inside.
5a) The flood switch is on the bottom of dishwasher, with black and yellow wires attached.
6a) If the bottom of the dishwasher has water in it, locate the plumbing problem and fix it, then dry it out.
6b) If there's junk wedged under/around the switch or float foam, then remove it all.
6c) If you know how, you can remove the switch and test that it works with a multimeter.
7) Plug the dishwasher back in temporarily, and check that it just beeps once like it's supposed to. Then unplug it again.
8) Replace the first cover. Reattach the two earth wires. Replace the second cover.
9) Plug in the dishwasher, fill it up with the dirty dishes and wash them.
HandyHubby, February 2009