Trane TVR Pro CO Series Service Manual page 90

2.15 H8: High pressure sensor error
Digital display output
Description
 High pressure sensor error.
 All units stop running.
 Error code is only displayed on the unit with the error.
Trigger / recover condition
 Trigger condition: Discharge pressure ≤ 0.3MPa.
 Recover condition: Discharge pressure > 0.3MPa.
 Reset method: Resume automatically.
Possible causes
 Pressure sensor not connected properly or has malfunctioned.
 Insufficient refrigerant.
 Low pressure side blockage.
 Poor evaporator heat exchange.
 Main PCB damaged.
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