Re: beko tzda627fw e4 fault code
If you need to change the evaporator you need to regass the fridge freezer which isn’t a DIY job I’m afraid.
But, your information is a bit incorrect according to Beko.
E4 is a defrost heater error. The defrost time has gone on four times inside one hour and then the heater failure error is displayed.
I would have thought that would indicate a fault with either the defrost sensor or the defrost heater and that replacement of the evaporator was not required.
HTH
K.