Service and Parts Manual (2018, 2019, 2020, 2021, 2022)

Table Of Contents
24 PB
OPERATION
Function and Control
7) IPM fault protection
When IPM faults, include overheat, unit will be shut down and all outputs are shut down. Control panel displays the
error code.
8) Temperature sensor fault protection
Any temperature sensor faults will shut down unit. The error code will be displayed
.
9) Communication fault protection
If communication faults between indoor unit and outdoor unit for continuously 2 minutes, unit will shut
down and display error code.
10) Compressor starting fault
If compressor fails to start, it will try to restart after 3 minutes. Error code will not be displayed for the rst 3
attempts to restart. If the copressor fails to start on the 4th try, it will not attempt restart any more and an error code
will occur.
11) DC-BUS overvoltage/undervoltage protection
If the unit senses the DC-BUS is overvoltage or undervoltage, the unit stops and an error code will occur.
12) EEPROM fault
When the unit is powered up, if system monitors the EEPROM chip fault (broken chip or incorrect data),
control panel displays error code and will not operate any more.