Cause : INLET LOW comes when pressure at pump/fan inlet too low. The "INLET LOW" alarm on an ABB ACS310 drive typically indicates a problem with the input signal or a parameter related to the inlet, such as low input voltage, pressure, or flow rate, depending on the specific application the drive is being used for.

1. Check for a closed valve on the inlet side of the pump/fan.
2. Check piping for leaks.
3. See parameter group 44 PUMP PROTECTION.