Panasonic CS-A24BB4P Service Manual

Also see for CS-A24BB4P: Operating instructions Service manual

Contents

Panasonic CS-A24BB4P Service Manual Manual pdf 92 page image

Emergency operation•• Emergency operation of outdoor unitEmergency operation can be carried out by setting theDSW1 switch on the printed circuit board of the outdoorunit to the EMERGENCY position. However, emergencyoperation is only carried out when an abnormality isdetected by the indoor/outdoor temperature thermistors.The resistance values of each thermistor are measuredas shown in the table below to determine if there is anabnormality.Thermistor resistance tableTemperature Resistance value (kΩ) ± 5%Room temperaturethermistorPipe temperaturethermistor-20°C 205.8 197.8-10°C 114.6 111.9-5°C 87.3 85.40°C 67.0 65.85°C 51.8 51.010°C 40.4 39.915°C 31.7 30.720°C 25.1 25.025°C 20.0 20.030°C 16.1 16.040°C 10.4 10.650°C 6.9 7.160°C 4.7 4.970°C ---- 3.580°C ---- 2.590°C ---- 1.8100°C ---- 1.4The pipe temperature thermistor resistance value arethe same for the indoor and outdoor units.occurred>−− Set only the thermistor which shows an abnormalityto the condition as shown in the table below to carryout emergency operation.Thermistor Cooling mode Heating modeIndoor unit Room temperature Fixed at 25°CPipe temperature Shorted OpenThermistor Cooling mode Heating modeOutdoor unit Discharge temperature Open ShortedHeat exchanger outlettemperatureShorted Open−− Refer to the circuit diagram for the connectionlocations for each thermistor.−− If there is an abnormality in the room temperaturethermistor, the temperature will be fixed at 25°Cregardless of the remote control display.NOTE:−− Any abnormalities detected by the temperaturethermistors are ignored during emergency operation,therefore, long-term operation in this mode shouldbe avoided.−− After emergency mode operation has beencompleted and normal operation is to be resumed,turn off the power supplies for the indoor andoutdoor units and set the DSW1 switch to NORMALposition.−− Self-diagnosis LEDs 4 to 6 will flash duringemergency operation.26 EMERGENCY OPERATION92CASSETTE TYPE