ABB ACH550 Error 4002: INP PHASE B LOSS

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

Alarm code4002

INP PHASE B LOSS occurs when phase B input is lost, often due to loose wiring or voltage issues. The manual's first action is: “Check J8 connector Check black wire on input block Check incoming voltage, phase to ground”

Model
ABB ACH550
Display shows
INP PHASE B LOSS (4002)
Type
Alarm code
Source
Manual p. 72

What 4002 means

INP PHASE B LOSS p. 72

Common causes

  • Alarm will occur in drive mode. In bypass, alarm will occur if bypass contactor has not closed. Unit will trip on Fault 3011 if the bypass contactor is closed p. 72
  • Loose J8 connector p. 72
  • Loose wiring on Contactor assembly. p. 72
  • Blown upstream fuse p. 72

What to do

  1. Check J8 connector Check black wire on input block Check incoming voltage, phase to ground p. 72

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

If 4002 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 72 All ACH550 error codes Manual details & download

This page summarises what the manufacturer’s manual says about 4002; 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.