Lennox LI009HI-230P432, Service Manual

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67
Installation and Maintenance
Service Manual
Analysis or processing of some of the malfunction display:
1. Compressor discharge protection
Possible reasons: shortage of refrigerant; blockage of air filter; poor ventilation or air flow short pass for condenser;the system has
noncondensing gas (such as air, water etc.); blockage of capillary assy (including filter); leakage inside four-way valve causes incorrect
operation; malfunction of compressor; malfunction of protection relay; malfunction of discharge sensor; outdoor temperature too
high.
Processing method: refer to the malfunction analysis in the above section.
2. Low voltage overcurrent protection
Possible reason: Sudden drop of supply voltage.
3. Communic ation malfun ction
Processing method: Check if communic ation signal cable is connected reliably.
4. Sensor open or short circuit
Processing method: Check whethers ensor is normal, connected with the corre sponding position on the controller and if damage of
lead wire is found.
5. Compressor over load protection
Possible reasons: insufficient or too much refrigrant; blockage of capillary an dincrease of suction temp.; improper running of
compressor, burning in or stuck of bearing, damage of discharge valve; malfunction of protector.
Processing method: adjust refrige rant amount; replace the capillary; replace the compressor; use univers al meter to check if the
contactor of compress or is fine when it is not over heated, if not replace the protector.
6. System malfun ction
Overload protection.When tube 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 beactivated.
Possible reasons: Outdoor tempera ture is too high when cooling; insufficient outdoor air circulation; refrigerant flow malfunction.
Please refer to the malfunction analysis in the previous section for handling method .
7. IPM module protection
Processing method:Once the module malfunction happens,if it persists for a long time and can not be self-canceled, cut off the
power and turn off the unit,and then re-energize the unit again after about 10 min.After repeating the procedure for sever times, if
the malfunction still exists,replace the module.