Fault code3020
PHASE SEQ means phase sequence is unknown at wiring time, requiring wire swap. The manual's first action is: “Swap any two of the three input wires to the bypass unit”
- Model
- ABB ACH550
- Display shows
- PHASE SEQ (3020)
- Type
- Fault code
- Source
- Manual p. 69
What 3020 means
PHASE SEQ p. 69
Common causes
- Phase sequence unknown at time of wiring p. 69
What to do
- Swap any two of the three input wires to the bypass unit p. 69
Before you service the product, read the safety instructions in the manual p. 2.
If 3020 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.”
This page summarises what the manufacturer’s manual says about 3020; 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.