Troubleshooting SiBE06112183 Service Diagnosis4.5 Radiant Panel Temperature Rise, Indoor ElectronicExpansion Valve (Motor Operated Valve) Abnormality,Freeze-up Protection ControlRemoteControllerDisplayA9Method ofMalfunctionDetectionRadiant panel temperature riseDuring RADIANT operation, high temperature control (e.g., operation halt, indoor electronicexpansion valve closure) is activated according to the temperature detected by the radiantpanel thermistors.Indoor electronic expansion valve abnormalityThe indoor electronic expansion valve is required to be fully closed during cooling, dry orheating operation. When the indoor electronic expansion valve is open due to malfunction, therefrigerant flows into the radiant panel and the radiant panel temperature rises or drops.The indoor electronic expansion valve is required to be open during RADIANT operation. Whenthe indoor electronic expansion valve is closed due to malfunction, the refrigerant does not flowinto the radiant panel and the radiant panel temperature does not rise.Operation stops when any of these cases is detected by the system.Freeze-up protection controlThe temperature detected by the radiant panel thermistors is used to prevent the indoor unitfrom freezing during cooling operation.MalfunctionDecisionConditionsRadiant panel temperature riseThe radiant panel surface temperature calculated by the radiant panel thermistors is above70°C.Indoor electronic expansion valve abnormality During cooling or dry operation, the temperature detected by the radiant panel thermistor(φ 4) has dropped. During heating operation, the temperature detected by the radiant panel thermistor (φ 4) hasrisen. During RADIANT operation, the temperature detected by the radiant panel thermistor (φ 4)does not rise.Freeze-up protection controlDuring cooling operation, the operation stops when the temperature detected by the radiantpanel thermistor (φ 4) has dropped.SupposedCauses Clogged air filter of the indoor unit Dust accumulation on the indoor heat exchanger Short-circuited air Defective radiant panel thermistor(s) Defective indoor heat exchanger thermistor Defective room temperature thermistor Defective indoor electronic expansion valve (or coil)
