!!
critical Itho Daalderop
Error Code LED blinks red rapidly
Signifies a hardware error or critical malfunction, system lockout.
? What Causes This
Critical errors in operation preventing normal service.
✓ How to Fix It
Appliance resets itself up to 3 times. Seek service immediately if unresolved.
Source: page 34 of the official manual
From the manual
This error code appears in:
Itho Daalderop 120l Smart Upp Boiler