Sanyo AHX0752 - Manual (Page 80)

3-18
Trouble Diagnosis
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3. W-2WAY ECO-i Alarm Codes
P03, P17, P18 Alarm
Alarm code P03, P17, P18
Alarm meaning Compressor 1 discharge temperature trouble; Compressor 2 discharge temperature trouble;
Compressor 3 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)
(3)
Operation failure of mechanical valve 3
(2) Clogging of mechanical valve 3
(4)
(5)
Insufficient amount of refrigerant (including trouble resulting from an insufficient initial charge
and from gas leakage)
Blocking of low-pressure parts caused by intrusion of foreign objects (moisture, scale, etc.)
(6)
Crossing (tubing or PCB connectors) with the other compressor thermistor
(7)
Expansion valve operation failure
(8)
Accumulation of refrigerant at stopped outdoor units
(9)
Compressor discharge sensor failure
PCB failure (A/D conversion failure)
Check (1) Operation failure of mechanical valve 3
Trouble: The compressor discharge temperature does not decrease even when
mechanical valve 3 is opened to 480 pulses.
Check:
Trouble:
(2) Clogging of mechanical valve 3
Trouble: The compressor discharge temperature does not decrease even when
mechanical valve 3 is ON.
Check: If mechanical valve 3 is open to 480 pulses, then check whether or not the
secondary side of the valve is cold.
(3) Insufficient refrigerant
Liquid effectiveness is poor.
Check: 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).
(4) Foreign object intrusion
Trouble: Liquid valve effectiveness is poor.
Check: Check that there is no difference in the condensation or frost conditions between the
strainer primary-side and secondary-side tubing.
(5) Crossed thermistor
Trouble: The discharge temperature of the other compressor is high although only this
compressor is operating.
When the liquid valve turns ON, the discharge temperature of the other compressor
decreases.
Trouble: • System is OK when all outdoor units are operating, however symptoms of
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.
Check: • In some cases, leakage may be occurring from the evaporator mechanical valve
or mechanical valve 3 at a stopped outdoor unit.
(7) Sensor failure
Check: • This alarm is likely to occur when wiring is partially cut. (It is difficult to identify, even
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.
(6) Accumulation of refrigerant in stopped outdoor units
Correction (1) Replace the sensor.
(2) Replace the outdoor unit PCB.
(3) Correct the problem locations.
Example All of the probable causes
Notes Operates continuously for a set length of time.
Indicates 2.5 minutes or longer for an inverter compressor (compressor 1) and 30 seconds or
longer for a constant-speed compressor (compressor 2 and 3).
Check whether or not mechanical valve 3 makes a grinding sound when the power is reset.