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Part 4 - Diagnosis and T
roubleshooting
4.15 P9 Troubleshooting
4.15.1 Digital display output
4.15.2 Description
▪ High temperature difference between water side heat exchanger water inlet and water outlet temperatures
protection.
▪ All units stop running.
▪ Error code is displayed on main PCB and user interface.
4.15.3 Possible causes
▪ Temperature sensor not connected properly or has malfunctioned.
▪ Water piping contains air.
▪ Insufficient water flow.
▪ Main PCB damaged.