Bosch Climate 8000i Service Manual

Function and Operation of Protective Procedures15Climate 8000i/8100i – 6721840685 (2021/05)[1] To terminal board (2) (Red)[2] To terminal board ( ) (Green/Yellow)[3] To terminal board (N) (Blue)[4] From 4-way Valve[5] From Expansion Valve[6] From Thermistor[7] From Fan motor[8] To compressor Orange[9] To compressor White[10] To compressor Red[11] To terminal board (1) (Brown)[12] To reactor (Gray)[13] To reactor (White)4 Function and Operation of ProtectiveProcedures4.1 Control4.1.1 Restart ControlOnce the compressor stops operating, it will not restart for 180 secondsto protect the compressor.Therefore, if the operating compressor is shut down from the remotecontrol and then turned back on immediately after, the compressor willonly restart after a delay time.(The indoor unit will restart operation immediately after the ON switch isoperated on the remote control.).4.1.2 Indoor unit heat exchanger freeze prevention controlIf the temperature of the indoor unit heat exchanger remains below 0 °Cfor 4 consecutive minutes during cooling or dehumidifying operation,the compressor operation stops temporarily in order to prevent freezing.When the temperature of the indoor unit heat exchanger rises to 2 °C orhigher after about 180 seconds, the compressor restarts and resumesnormal operation.4.1.3 Outdoor unit overheat prevention controlDuring cooling operation, if the temperature of the outdoor unit heatexchanger exceeds the outdoor unit heat exchanger overheat preventiontemperature (about 55 °C), the operating frequency is decreased byabout 4 to 15 Hz.Then, this operation is repeated every 60 seconds until the temperatureof the outdoor unit heat exchanger drops to about 54 °C or lower. Oncethe temperature of the outdoor unit heat exchanger drops to about 54 °Cor lower, the operating frequency is increased by about 4 to 10 Hz every60 seconds until the normal operation condition resumes. If thetemperature of the outdoor unit heat exchanger exceeds the outdoorunit heat exchanger overheat protection temperature for (120 seconds:outdoor temperature ≥ 40 °C • 60 second: outdoor temperature< 40 °C) at minimum operating frequency, the compressor stopsoperating and then restarts after about 180 seconds, and the abovementioned control is repeated.4.1.4 Compressor overheat prevention controlIf the temperature of the compressor exceeds the compressor overheatprevention temperature (110 °C), the operation frequency is decreasedby about 4 to 10 Hz.Then, this operation is repeated every 60 seconds until the temperatureof the compressor drops below the overheat protection temperature(110 °C). Once the temperature of the compressor drops below theoverheat protection temperature, the operating frequency is increasedby about 4 to 10 Hz every 60 seconds until the normal operationcondition resumes. If the temperature of the compressor exceeds theoverheat protection temperature for a certain time (120 sec: outdoortemperature ≥ 40 °C • 60 seconds: outdoor temperature < 40 °C) atminimum operating frequency, the compressor stops operating and thenrestarts after about 180 seconds, and the above control is repeated.4.1.5 Start up controlWhen the air conditioner starts in the cooling mode, if the roomtemperature is 2 °C higher than the set temperature the air conditioneroperates with the operating frequency at maximum.When the air conditioner starts in the heating mode, if the roomtemperature is 5.3 °C lower than the set temperature the air conditioneroperates with the operating frequency at maximum. Then, when the settemperature is reached, the air conditioner operates at the operatingfrequency determined by fuzzy logic calculation, then enters the normalcontrol.4.1.6 Outdoor unit fan delay controlThe compressor stops immediately after cooling or dehumidifying orheating operation is shut down, but the outdoor unit fan continuesoperation for 50 seconds.4.2 Protection Device Functions and OperationsThese models have following thermistors• Indoor unit: TH1, TH2• Outdoor unit: TH1, TH2, TH3, TH4, TH5The errors for the thermistors that are not mentioned above areirrelevant.These indoor units don’t have power relay.Operation Self-diagnosisresult displayFunction Description Detection period Reset condition Indoor unit errordisplayIndoorunitOutdoorunit1 Indoor unit fan lock Operation stops if there is no input ofrotation pulse signal from indoor unit fanmotor for 1 minute.When indoor unitfan is in operationOperation OFF or ON After a single errorjudgment(completeshutdown).Yes NoneIndoor unit fanrotation speed errorOperation stops if rotation pulse signalfrom indoor unit fan indicatesabnormally low speed (about 300 rpmor slower).When indoor unitfan is in operationOperation OFF or ON After a single errorjudgment(completeshutdown).Yes None2 2-way valve freezepreventionCompressor stops if temperature ofoutdoor unit 2-way valve remains below0 °C for 10 continuous minutes duringcooling or dehumidifying operation.When in cooling ordehumidifyingoperationAutomatic resetwhen temperature of2-way valve risesabove 10 °C.None None Yes