Si04-402A Problem Symptoms and MeasuresService Diagnosis 692. 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 21°C or higher (onlyfor heat pump model), and cooling operationcannot be used when the outside temperatureis below 10°C.—Diagnosis with remote controllerindication — 73Check 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 21°C or higher (onlyfor heat pump model), and cooling operationcannot be used when the outside temperatureis below 10°C.—Diagnosis with remote controllerindication — 73Equipment 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— 73Diagnosis by service port pressureand operating current Check for insufficient gas. 109Large operating noise andvibrationsCheck the output voltage of thepower transistor.— 110Check the power transistor. — —Check the installation condition. Check to make sure that the required spacesfor installation (specified in the TechnicalGuide, etc.) are provided.—
