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Analysis or treatment of some of the display failures
1. Compressor discharge protection
Possible causes: coolant not sufficient, air filter net is blocked, condenser is of poor ventilation or air flow
is shorted, there is non-condensed gas in the system (such as air, water, etc.), capillary assembly
(including filter) blockage, inner leakage in the 4-way valve, leading to mistaken action; compressor itself
is with failure, failure is with protection relay itself, failure in exhaust temperature sensor and too high an
outdoor temperature.
Remedy: refer to the malfunction analysis in the above section.
2. Low voltage over current protection:
Possible reason: Sudden drop of supply voltage.
3
Communication Malfunction:
Remedy: Check if communication signal cable is connected reliably
4
Open or short circuit with temperature sensor:
Remedy: Check whether sensor is normal, connected with the corresponding position on the controller
and if damage of lead wire is found
5. Compressor over load protection:
Possible reasons: shortage of refrigerant; blockage of capillary and increase of suction temperature;
improper running of compressor, burning in or stuck of bearing, damage of discharge valve; malfunction
of protector.
Remedy: adjust the coolant amount, change capillary, replace the compressor, check the compressor
with a multimeter and see if it conducts when it is not over heated, and replace the protector if it does not
conduct.
6. System malfunction
i.e. overload protection. When pipe temperature (Check the temperature of outdoor heat exchanger
when cooling and check the temperature of indoor heat exchanger when heating) is too high, protection
will be activated.
Possible causes: too high an outdoor temperature when cooling, air ventilation outdoor is not sufficient
or failure in coolant flow.
Remedy: refer to the malfunction analysis in the above section.
7. The cooling pressure is about 0.9Mpa and the heating pressure is about 3.0 Mpa when the frequency
converter split system is operating normally. If the pressure is lower than the normal range, there is
possibly leakage. If it is higher than the normal range, it is possibly due to too much coolant or air mixing
in the system. The pressure also depends on various conditions.
8. IPM module protection(H5):
Remedy:
Check if the voltage between power module P and N is too low (when input
voltage is lower than 178V, the compressor will stop); if the current is too high
(when the input D.C. is higher than 46A, the compressor will stop). In normal
condition, voltage between P and N should be 310V
Normal
Temperature of power module is too high,
which causes overheating protection
Still indicating protection
Confirm the setting status of outdoor unit
(cooling)
Nothing abnormal
Check the power circuit of outdoor unit(PTC resistor,
rectifier bridge, reactor aNd capacitor for failure).
Check if radiating paste is
spread evenly or radiating
sticker is stuck well; if screws
of power module is tightened
Poor radiation, heat exchanger is dirty
—97—
Abnormal
Reinstall power module
and re-spread radiating
paste or stick radiating
sticker on the radiator of
power module.
Remove obstructions
and clean
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