Haier 1U71S2SG1FA Service Manual

Also see for 1U71S2SG1FA: Installation manual Service manual Installation manual

Contents

173Maintenance of Intrinsically Safe ElementsWeldingRemoval and Vacuumizing• The intrinsically safe element refers to the components working continuously inside flammable gas without anyrisks.• Before any maintenance, leak detection and inspection on earthing reliability of the air conditioner must be carriedout, to ensure no leakage and reliable earthing.• In case the allowable voltage and current limit may be surpassed during the service of the air conditioner, anyinductance or capacitance cannot be added in the circuit.• Only the elements appointed by the air conditioner manufacturer can be used as the parts and componentsreplaced, or otherwise a fire or explosion may be triggered in case of refrigerant leakage.• For the maintenance not involved in system pipelines, the system pipelines shall be well protected, to ensure thatno leakage will be caused due to maintenance.• After maintenance and before test run, the air conditioner must be subject to leak detection and inspection onearthing reliability with leak detection equipment or leak detecting solution. It shall be guaranteed that the startupinspection is carried out without leakage and under reliable earthing.• Favorable ventilation must be guaranteed in the maintenance area. After the maintenance machine is subject tothe vacuumizing above, the system refrigerant can be discharged on the outdoor unit side.• Before the outdoor unit is welded, it must be guaranteed that no refrigerant is inside the outdoor unit and thesystem refrigerant has been discharged and cleared.• The refrigeration pipelines cannot be cut with a welding gun under any circumstance. The refrigeration pipelinesmust be disassembled with a pipe cutter, and the disassembly must be carried out around a ventilation opening.• The maintenance or other operations of the refrigeration circuit shall be made as per conventional procedures.Moreover,the flammability of refrigerant shall also be mainly considered. The following procedures shall be followed:• Refrigerant cleaning;• Pipeline purification with inert gas;• Vacuumizing;• Pipeline purification again with inert gas;• Pipeline cutting or welding. The refrigerant shall be recovered to a proper cylinder. The system shall be purgedwith OFN, to ensure safety. The step above may need to be repeated for several times. Compressed air or oxygencannot be used for purging.In the course of purging, OFN shall be charged inside the refrigeration system under vacuum state, to reach theoperating pressure. Afterwards, the OFN shall be discharged to the atmosphere. Finally, the system shall bevacuumized. The step above shall be repeated until all the refrigerants in the system are cleared. The OFN chargedfor the last time shall be discharged to the atmosphere. Afterwards the system can be welded. The operation aboveis necessary in case of pipeline welding.It shall be guaranteed that no alight fire source is around the outlet of the vacuum pump and the ventilation isfavorable.