Trane TVR Pro CO Series Service Manual page 74

2.10 F3, F5: Temperature sensor (T6B/T6A) error
Digital display output
Description
 F3 indicates plate heat exchanger cooling refrigerant outlet temperature sensor (T6B) error.
 F5 indicates plate heat exchanger cooling refrigerant inlet temperature sensor (T6A) error.
 All units stop running.
 Error code is only displayed on the unit with the error.
Trigger / recover condition
 Trigger condition: Temperature sensor T6A(B) is open or short-circuit.
 Recover condition: Temperature sensor T6A(B) connection ports can detect load.
 Reset method: Resume automatically.
Possible causes
 Temperature sensor not connected properly or has malfunctioned.
 Damaged main PCB.
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