Trane 4TVH0086FE000AA Service Manual page 111

2.15 P1: Discharge pipe high pressure protection
Digital display output
Description
 Discharge pipe high pressure protection. If the system has a 3-phase protector and the 3-phase protector is connected
with the high pressure switch, the system will display P1 protection when initially powered on, and P1 protection will
disappear once the system reaches a steady state.
 All units stop running.
 Error code is only displayed on the unit with the error.
Trigger / recover condition
 Trigger condition: Discharge pressure ≥ 4.4MPa.
 Recover condition: Discharge pressure ≤ 3.2MPa.
 Reset method: Resume automatically.
Possible causes
 Outdoor unit stop valves are closed.
 Pressure sensor/switch not connected properly or has malfunctioned.
 Excess refrigerant.
 System contains air or nitrogen.
 High pressure side blockage.
 Poor condenser heat exchange.
 Main PCB damaged.
Procedure
ODU stop valves are closed
High pressure sensor connection on main
High pressure sensor has short-circuited
P1
No
PCB is loose
1
No
or failed 2
No
Yes
Open the stop valves
Yes
Ensure the sensor is connected properly
Yes
Replace the sensor
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