If you are getting the 20 error code but there is no water inside the dishwasher it may be caused by a fault on the system that reports the presence of water inside the machine. In this situation I would call in an engineer – finding an appliance engineer.
If the dishwasher is full of water
Draining a dishwasher full of water can be tricky because ideally you need to remove or disconnect the drain hose at the back and lower it into a bowl. However, dishwashers can be difficult to pull out especially if full of water. The extra weight can contribute to damaging the flooring too. You can of course ladle the water out. Remove the lower basket and start scooping with an appropriate vessel.
Possible causes of dishwasher full of water
Once most of the water has been removed you have to consider what the problem is. Dishwashers can be difficult to work on so I don’t advise delving too deeply. Most parts are in the base of the machine with no back panel to remove to get at them. Some need the lid, and side panels and kick strips etc. all taking off to get to parts. Do not turn a dishwasher upside down.
One of the most likely causes is a blockage somewhere although the pump could have failed. Things I would try before calling in an engineer are removing the drain hose from the u-bend connection under the sink (if that’s how it’s connected) and checking inside the plastic spigot at the end of the drain hose and inside the plastic connection on the u-bend for obstructions. Also, remove the big filter in the base (under the spray arm) and carefully check for obstructions in the channel leading into the drain pump.
Fixed-price repairs, Pay monthly, Repair & protect your whole appliance..
Price match promise: "If you find the exact same part cheaper, we’ll not only match it, we’ll beat it!"