Welcome to Just answer
How old is it ?
not sure, 3-4 years
ok...F8 error means heater relay cannot be activated...check the connections to the heater and to the control board
was there a power outage ?
seems like you are not here...anyways What you have to do is unplug the unit and then take the washer out and then take its rear off...check the wiring to the heater and then check the wiring from the heater to the control....disconnect and reconnect the wires...Give the relays a tap on the pcb as it could be stuck....after this is done plug it back and check if the problem is solved...if the problem is not solved then you will have to test the heater and main board, and replace the part that is bad