Manual available here:
http://service.baumatic.co.uk/manuals/bdwi440-201112.pdf
Fault codes listed here:
http://www.ukwhitegoods.co.uk/help/fault-codes/dishwasher-fault-codes/3305-baumatic-bdw-dishwasher-fault-codes
E3
Dishwasher has detected that water has not been heated in allotted time
Check heating element
Check operation of thermostats
Check wiring
Water heating element defective
Check electronic controller
All reasonably easy for someone COMPETENT to do.
XXX
December 2016