Diagnosis
A sensor fault. Err1 typically indicates an open-circuit temperature sensor in the top zone. Err2 points to the bottom zone sensor.
How to Fix It
For Err1 or Err2, perform a hard reset. Unplug the unit from the wall for 5 full minutes. This clears the controller's memory. Plug it back in. The error may clear. If it returns immediately, the corresponding sensor or its wiring is defective.
If That Didn't Work
The sensor is a small probe near each heating element. You cannot access it without disassembly. Do not try. A persistent Err code requires warranty service or board replacement.
Heads Up
Do not continue operating with an Err code. The control system cannot regulate temperature safely, leading to burning or fire risk. Unplug the unit until repaired.