So the problem is the heater is not working. You need to find out why by fault finding using test meter & tools. Sorry I can't tell you why it is not heating as I am not there and can't see or test anything for you. It could be a faulty heater element, broken wire going to the heater, no power going on to heater due to a faulty timer or circuit board, not enough water in the sump or wash [ump not working and not making any water flow through the heater. Many reasons, if you can't do fault tracking or don't have any tools & test meter then you will have to call out a service person.
Lincoln Appliance NZ, December 2018