Hello My name is Ian ~ I am not on the site constantly so please be patient whilst waiting for responses to you queries ~ there are two ways to connect it to prevent back syphoning, ~ a. Connect it to a standard drain pipe using the u bend provided with the appliance and ensuring that the drain pipe that you hook the drain hose into is at least two thirds of the way up the back of the appliance ie the bend is above two thirds of the height of the appliance b. Use the spigot under the sink but take the grey drain hose out of the spigot and then loop it up the side of the sink in an inverted U and then back out to the dishwasher, this will ensure that no water can syphon back into the sump of the dishwasher when you pull the sink plug. With the latter make sure you cut off the end of the spigot or remove the plug before fixing the drain hose.
Having given you the information requested would you now kindly rate the service using the smiley faces below, this allows me to shut down the information request on the system but lets you ask further questions on a foc basis. Thanks for the question, Ian
Does this comply with fluid category 3?
My understanding of Fluid Category 3 is that it is only applicable to Industrial and Commercial installations/processes. As this is a domestic use appliance it is not covered by FC3; although the original post gives, if installed correctly an air break to stop back syphoning of waste water.