SiBE04-809 Problem Symptoms and MeasuresService Diagnosis 732. Problem Symptoms and MeasuresSymptom Check Item Details of Measure ReferencePageNone of the units operates. Check the power supply. Check to make sure that the rated voltage issupplied. —Check the type of the indoor units. Check to make sure that the indoor unit type iscompatible with the outdoor unit. —Check the outdoor air temperature. Heating operation cannot be used when theoutdoor air temperature is 20°C or higher (onlyfor heat pump model), and cooling operationcannot be used when the outside temperatureis below 10°C.—Diagnosis with remote controllerindication — 77Check the remote controlleraddresses. Check to make sure that address settings forthe remote controller and indoor unit arecorrect.—Operation sometimesstops. Check the power supply. A power failure of 2 to 10 cycles can stop airconditioner operation. (Operation lamp OFF) —Check the outdoor air temperature. Heating operation cannot be used when theoutdoor air temperature is 20°C or higher (onlyfor heat pump model), and cooling operationcannot be used when the outside temperatureis below 10°C.—Diagnosis with remote controllerindication — 77Equipment operates butdoes not cool, or does notheat (only for heat pumpmodel).Check for wiring and piping errors inthe indoor and outdoor unitsconnection wires and pipes.Conduct the wiring/piping error check describedon the product diagnosis nameplate. —Check for thermistor detection errors. Check to make sure that the main unit’sthermistor has not dismounted from the pipeholder.—Check for faulty operation of theelectronic expansion valve. Set the units to cooling operation, and comparethe temperatures of the liquid side connectionpipes of the connection section among rooms tocheck the opening and closing operation of theelectronic expansion valves of the individualunits.—Diagnosis with remote controllerindication — 77Diagnosis by service port pressureand operating current Check for insufficient gas. 121Large operating noise andvibrations Check the output voltage of thepower transistor. — 122Check the power transistor. — —Check the installation condition. Check to make sure that the required spacesfor installation (specified in the EngineeringData Book, etc.) are provided.—
