Troubleshooting SiBE04-10190 Service Diagnosis4.4 Operation Shutdown Due to High-Pressure Control or Freeze-Up Protection(Thermistor Activation)Remote ControllerDisplayA5Indoor unit LEDDisplayMethod ofMalfunctionDetection High pressure controlDuring heating operations, the temperature detected by the indoor heat exchanger thermistor is usedfor the high pressure control (operation stop) The freeze protection control (operation halt) is activated during cooling operation according to thetemperature detected by the indoor unit heat exchanger thermistor.MalfunctionDecisionConditions High pressure controlDuring heating operations, the temperature detected by the indoor heat exchanger thermistor is above67˚C Freeze-Up protectionWhen the indoor unit heat exchanger temperature is below 0˚C during cooling operation.Supposed Causes Operation halt due to clogged air filter of the indoor unit. Operation halt due to dust accumulation on the indoor unit heat exchanger. Operation halt due to short-circuit. Detection error due to faulty indoor unit heat exchanger thermistor. Detection error due to faulty indoor unit PCB.TroubleshootingCheck No.1Refer to P.119NONONOCheck No. 1Indoor unit heat exchangerthermistor checkCheck the intake air filter.Check the air passage.YESYESCheck the dust accumulation onthe indoor unit heat exchanger.YESYESIs there any short-circuit?Is it very dirty?Is it very dirty?Does it conform to thethermistor characteristicchart?NOProvide sufficient air passage.Clean the air filter.Clean the heat exchanger.Replace the indoor unit PCB(1).Replace the thermistor.(R1170)CautionBe sure to turn off power switch before connect or disconnect connector,or parts damage may be occurred.SiBE04-101.book Page 90 Monday, October 15, 2001 3:08 PM
