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Accommodation climate is to be maintained at comfortable level. Air conditioning should accordingly done to adjust to hot/cold weather conditions. CE must ensure that the A/C compressor is being operated and maintained in good order and system is free of leaks. CE must take daily rounds of AC room to verify proper operation of A/C plant and air handling unit.
• Suction air filters must be kept clean at all times.
• There should not be any frosting on the AC compressor cylinder head, it is indication of liquid carry over and can destroy the compressor. Liquid carry over may be due to wrong operation in cold weather/ faulty unloader or choked evaporator coils.
• There should by atleast 50% refrigerant level in the sight glass of the condenser.
• Ensure that oil separator is working well.
• Before carrying out any maintenance on the A/C plant the refrigerant must by pumped down from the system and collected in the liquid receiver. REFERIGERANT SHOULD NOT BE VENTED OUT.
• In case maintenance is required on the condenser/liquid receiver, refrigerant is to be recovered from the system and transferred to empty refgn bottles. After completion of repairs system is to vacuum out using vacuum pump and refrigerant is to be charged back. Charging is to be done thru the refrigerant dryer.
• Regular leak checks are to be carried out. Any leak found is to be immediately rectified. Proper records are to be made of refrigerant that has been charged.
Provision chambers temperatures are to be properly maintained. CE should carry out daily checks of provision compressor and provision chambers.
• It must be ensured that the door packing of the provision chambers is free of ice and sealing properly door heater is working good.
• Drain from the evaporators and provision chambers must be maintained clear.
• Evaporator coils and fans must be kept clean and clear of obstruction.
• Auto defrost cycle should be fully functional.
• Emergency alarm for man trap inside chamber should be regularly tested.
• Door latchet should be free to move and door should be able to open from inside the reefer chambers.All refrigeration system works like this
Compressor( High pressure, Hot gas refrigerant) > Condenser ( High pressure, Cooled liquid refrigerant) > Drier > Thermo expansion valve ( Low pressure, Cold liquid refrigerant) > Evaporator (Heat exchange takes place here, Low pressure, Hot Gas/Liquid refrigerant) > Compressor
Common problems i can think of.
1) Knocking of compressor indicates that liquid are returning to compressor. ( Clean the evaporator or condenser SW/FW side dirty, (Expansion valve settings)
2) Low suction pressure of compresser ( Refrigerent Top up )
3) Icing of evaporator (Ice room opened for too long causing higher humidity )
4) Low delivery pressure compressor valves leakage etc )
5) High delivery pressure ( Condenser dirty, not enough SW/FW)someone continue on the list !
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