Panasonic U-72MF1U9 Service Manual page 83

3. W-3WAY VRF Alarm Codes
P03, P17 Alarm
Alarm code P03, P17
Alarm meaning P03: Compressor 1 discharge temperature trouble.
P17: Compressor 2 discharge temperature trouble.
Alarm conditions Pre-trip stop at 222°F (106°C) or higher
This alarm occurs when the pre-trip counter reaches 4. However the counter is reset when the
compressor has operated continuously for a certain length of time.
Probable cause (1)
Operation failure of mechanical valve 3
(2) Clogging of mechanical valve 3
(3)
Insufficient amount of refrigerant (including trouble resulting from an insufficient initial charge
and from gas leakage)
(4) Blocking of low-pressure parts caused by intrusion of foreign objects (moisture, scale, etc.)
(5) Crossing (tubing or PCB connectors) with the other compressor thermistor
(6)
Expansion valve operation failure
(7) Accumulation of refrigerant at stopped outdoor units
(8) Compressor discharge sensor failure
(9) PCB failure (A/D conversion failure)
Check (1) Operation failure of mechanical valve 3
Trouble:
Check:
(2) Clogging of mechanical valve 3
Trouble: The compressor discharge temperature does not decrease even when
Check:
(3) Insufficient refrigerant
Trouble:
Check:
(4) Foreign object intrusion
Trouble:
Check:
(5) Crossed thermistor
Trouble: The discharge temperature of the other compressor is high although only this
(6) Accumulation of refrigerant in stopped outdoor units
Trouble: • System is OK when all outdoor units are operating, however symptoms of
Check: • In some cases, leakage may be occurring from the evaporator mechanical valve
(7) Sensor failure
Check: • This alarm is likely to occur when wiring is partially cut. (It is difficult to identify, even
The compressor discharge temperature does not decrease even when
mechanical valve 3 is opened to 480 pulses.
Check whether or not mechanical valve 3 makes a grinding sound when the power is reset.
mechanical valve 3 is ON.
If mechanical valve 3 is open to 480 pulses, then check whether or not the
secondary side of the valve is cold.
Liquid effectiveness is poor.
Check whether or not the superheating temperature is declining if the evaporator
mechanical valve is opened to 300 pulses or more (after checking for
foreign object intrusion).
Liquid valve effectiveness is poor.
Check that there is no difference in the condensation or frost conditions between the
strainer primary-side and secondary-side tubing.
compressor is operating.
When the liquid valve turns ON, the discharge temperature of the other compressor
decreases.
insufficient gas occur when a certain outdoor unit is stopped.
• Condensation or frost is visible up to the top of the accumulator of the stopped outdoor unit.
• After an outdoor unit stops, there is the sound of refrigerant flowing into an outdoor
unit that was stopped for a long time.
• When an outdoor unit starts after being stopped for a long time, the start is
accompanied by much vibration.
or mechanical valve 3 at a stopped outdoor unit.
when continuity is checked.) The detected discharge temperature is high.
• Although such conditions rarely occur, a P02 alarm is likely if the detected
discharge temperature is low.
• Replace the sensor with another discharge sensor and compare the temperature conditions.
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Trouble Diagnosis
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