!!
critical Itho Daalderop
Error Code E1
Hardware error — ROM memory defect
? What Causes This
Faulty control board or hardware issue.
✓ How to Fix It
The appliance resets automatically up to three times. Replace the control board if unresolved.
Source: page 38 of the official manual
From the manual
This error code appears in:
Itho Daalderop 120l Smart Upp Boiler