SERVICE MANUAL - Toshiba

PressuresensorFunctional part nameHigh pressure sensorLow pressure sensorFunctional outline(Connector CN501: Red)1) Detects high pressure and uses it to control the capacity of the compressor.2) Detects high pressure during all cooling operation and uses it to control the fan when coolingwith low outside air.3) Detects under-cool of the indoor unit of which heating thermo.-ON during all heating operationand simultaneous operation.4) Controls outdoor fan rpm during mainly cooling, part heating operation.(Connector CN500: White)1) Detects low pressure and uses it to control capacity of the compressor during all coolingoperation and simultaneous operation2) Detects low pressure and uses it to controls super heat during all heating operation andsimultaneous operationHeater Compressor case heater (Compressor 1 Connector CN316: White, Compressor 2 Connector CN315: Blue)1) Prevents liquid accumulation in the compressorAccumulator case heater (Connector CN321: Red)1) Prevents liquid accumulation to accumulatorBalance pipe1) Oil balancing pipe between outdoor unit (This unit does not use this Balance pipe.)Operation modeOperation mode1. All Indoor Unit(s)Operating for Cooling2. All Indoor Unit(s)Operating for HeatingOutlineOnly cooling operation without heating operationOutdoor heat exchanger (Main heat exchanger) is used as a condenser.Only heating operation without cooling operationOutdoor heat exchanger (Main heat exchanger) is used as an evaporator.3. Simultaneous operation MIU for simultaneous operation3-1. Mainly cooling, partlyheating operation3-2. Mainly heating, partlycooling operationCooling/heating simultaneous operation with subjective cooling operationOutdoor heat exchanger (Sub heat exchanger) is used as a condenser.Cooling/heating simultaneous operation with subjective heating operationOutdoor heat exchanger (Main heat exchanger) is used as an evaporator.4. Defrost Using the reversing operation of the 4-way valve, ice on the outdoor heat exchanger isdissolved within a single cooling cycle.For details of operation mode, refer to page 53 to 59.50