Siemens MICROMASTER 420 Error A0503: Undervoltage Limit

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

Warning codeA0503

The inverter has detected a voltage level below the minimum acceptable limit. The manual's first action is: “Check main supply voltage (P0210)”

Model
Siemens MICROMASTER 420
Display shows
Undervoltage Limit (A0503)
Type
Warning code
Source
Manual p. 72

What A0503 means

Undervoltage Limit p. 72

Common causes

  • Mains supply too low p. 72
  • Short mains interruption p. 72

What to do

  1. Check main supply voltage (P0210) p. 72

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

If A0503 is still not resolved

  • Contact your service dealer for assistance. p. 72
    “Check main supply voltage (P0210)”
Open the manual at page 72 All MICROMASTER 420 error codes Manual details & download

This page summarises what the manufacturer’s manual says about A0503; 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.