ABB ACH550 Error 18: THERM FAIL

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

Fault code18

THERM FAIL indicates an internal fault where the thermistor measuring drive temperature is open or shorted. The manual's first action is: “Contact your local ABB sales representative.”

Model
ABB ACH550
Display shows
THERM FAIL (18)
Type
Fault code
Source
Manual p. 25

What 18 means

THERM FAIL p. 25

Common causes

  • Internal fault. The thermistor measuring the internal temperature of the drive is open or shorted. p. 25

What to do

  1. Contact your local ABB sales representative. p. 25

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

If 18 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 25 All ACH550 error codes Manual details & download

This page summarises what the manufacturer’s manual says about 18; 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.