The washer cleans & empties no problem but when I run the tap in tne sink the sump(I think that's what it's called starts to fill up?

Lee, December 2013

if the drain hose is connected under a sink on the waste this will be the issue.Drain hose must go upwards from the spigot on the sink before going down to the dishwasher otherwise dirty water from the sink will run straight down in to the dishwasher sump as you say.Re route the drain hose upwards as high up under the sink before turning it downwards to the dishwasher

CK, December 2013