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Service Manual
9.3 How to Check Simply the Main Part of Outdoor
1. E1: High pressure protection
Malfunction description: The pressure of ODU high pressure side is too high.
Main check points:
a. Is the system pressure is normal;
b. Is the pressure switch is normal;
c. If above two issues are normal, the mainboard circuit is with malfunction, please replace mainboard.
2. E2: Freeze protection
Malfunction description: Too low tube temperature of IDU under cooling mode.
Main check point:
a. Check if the IDU fan speed is normal, if the air inlet/outlet is smooth;
b. Check if the IDU, ODU heat exchanger is too dirty that affect the heat exchanging effect.
3. E3: Low pressure protection
Malfunction description: The pressure of ODU low pressure side is too low
Main check points:
a. Is the system pressure is normal;
b. Is the pressure switch is normal;
c. If above two issues are normal, the mainboard circuit is with malfunction, please replace mainboard.
4. E4: The air discharging temperature is too high
Main check points:
a. Pull off the ODU air discharging temp. sensor, check if the temp. sensor resistance value match with present temperature;
b. Check if the refrigerant is too much or too little;
c. Check if the IDU, ODU heat exchanger is too dirty that affect the heat exchanging effect.
5. E6: IDU, ODU communication malfunction
Main check points:
a. Check if the wiring connection if IDU and ODU is correct;
b. Check if the communication power supply voltage is normal, if the DC voltage is more than 56±15%, please replace the ODU
mainboard.
6. F4: Outdoor condenser temperature sensor open or short circuit
Malfunction description: The ODU condenser temp. sensor temperature value is too high or too low that out of the normal range.
Main check points:
a. Pull off the ODU condenser temp. sensor, check if the temp. sensor resistance value match with present temperature;
b. If the temp. sensor resistance is normal, please replace ODU mainboard;
7. F3: ODU ambient temp. sensor open/short circuit
Malfunction description: The ODU ambient temp. sensor temperature value is too high or too low that out of the normal range.
Main check points:
a. Pull off the ODU ambient temp. sensor, check if the temp. sensor resistance value match with present temperature;
b. If the temp. sensor resistance is normal, please replace ODU mainboard;
8. F5:ODU air discharging temp. sensor open, short circuit
Malfunction description: The ODU air discharging temp. sensor temperature value is too high or too low that out of the normal
range.
Main check points:
a. Pull off the ODU air discharging temp. sensor, check if the temp. sensor resistance value match with present temperature;
b. If the temp. sensor resistance is normal, please replace ODU mainboard;
9. H3: Compressor overload protection
Malfunction description: Temperature of top compressor is over than the limit value
Main check points:
a. Normally the compressor overload protection switch is always on, check if the switch is normal.
10. H5: IPM module protection
Main check points:
a. Check if the compressor wiring connection is well connected, if the compressor wiring sequence is correct. The correct wiring
sequence is yellow, blue, red in anticlockwise direction.
b. Pull off the compressor connection wire, measure the impedance between phase U/V/W and P/N, if any of them is short
circuit, please replace the ODU mainboard;
c. Check if the compressor is damaged, measure the resistance between any two phases of the compressor three phases.
Installation and Maintenance
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