ABB ACH550 Error 3205: UNKNOWN CB

AC drive · taken from the manufacturer’s manual, pages cited

Fault code3205

UNKNOWN CB means the bypass control board type is unrecognized and firmware compatibility is required. The manual's first action is: “Firmware is not compatible with control board in RBCU. Firmware 93F and greater compatible with all RBCU hardware. Firmware 93D and earlier can only be loaded in RBCU Rev D and earlier.”

Model
ABB ACH550
Display shows
UNKNOWN CB (3205)
Type
Fault code
Source
Manual p. 71

What 3205 means

UNKNOWN CB p. 71

Common causes

  • Bypass control board type is unknown. p. 71

What to do

  1. Firmware is not compatible with control board in RBCU. Firmware 93F and greater compatible with all RBCU hardware. Firmware 93D and earlier can only be loaded in RBCU Rev D and earlier. p. 71

Before you service the product, read the safety instructions in the manual p. 2.

If 3205 is still not resolved

  • contact the factory or your local Authorized Service Center for repair or replacement. p. 2
    “Never attempt to repair a malfunctioning ACH550; contact the factory or your local Authorized Service Center for repair or replacement.”
Open the manual at page 71 All ACH550 error codes Manual details & download

This page summarises what the manufacturer’s manual says about 3205; each statement links to the page it comes from, and quoted lines are copied word for word. It is not a substitute for the manual or for a qualified installer. ManualLib is not affiliated with ABB. Found a mistake? Report an error.