Siemens MICROMASTER 420 Error A0702: CB warning 3

Siemens MICROMASTER 420 inverter · taken from the manufacturer’s manual, pages cited

Warning codeA0702

CB warning 3 indicates a problem with the communication board. The manual's first action is: “See CB user manual”

Model
Siemens MICROMASTER 420
Display shows
CB warning 3 (A0702)
Type
Warning code
Source
Manual p. 72

What A0702 means

CB warning 3 p. 72

Common causes

  • CB (communication board) specific p. 72

What to do

  1. See CB user manual p. 72

Before you service the product, read the safety instructions in the manual p. 6.

If A0702 is still not resolved

  • See CB user manual p. 72
    “See CB user manual”
Open the manual at page 72 All MICROMASTER 420 error codes Manual details & download

This page summarises what the manufacturer’s manual says about A0702; 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 Siemens. Found a mistake? Report an error.