Schematic Diagram of Refrigerant
| No. | Parts name | Symbol | (Electric symbol) | Function | ||
| Outdoor unit sensor | Outdoor thermistor | Ta | R1T (Th1) | In heating operation standby due to outdoor temperature (forcedly thermostat-off at 27°C or higher), influence to defrost condition. | ||
| Heat exchanger thermistor | Tb | R2T (Th2) | In heating operation, used for detection of defrosting | |||
| Discharge pipe thermistor | Tdi, Tds | R31T (Th3-1) R32T (Th3-2) | Used for protection control of discharge pipe temperature | |||
| Suction pipe thermistor | Ts | R4T (Th4) | In heating operation, used for superheated degree (SH = Ts – Te) control of outdoor electronic expansion valve | |||
| High-pressure sensor | Pc, Tc | (SENPH) | Used for high pressure control and for compressor capacity control in heating operation. Although the pressure (Pc) is detected, controlling should be based on the equivalent saturation temperature (Tc). | |||
| Low-pressure sensor | Pe, Te | (SENPL) | Used for low pressure control and for compressor capacity control in cooling operation. Although the pressure (Pe) is detected, controlling should be based on the equivalent saturation temperature (Te). | |||
| Indoor unit sensor | Suction air thermistor | Tr | R1T (Th1) | Used for thermostat control and compensation of electronic expansion valve control. | ||
| Liquid pipe thermistor | Tl | R2T (Th2) | Used for superheated degree (SH = Tg – Tl) control in cooling operation and freeze-up prevention control. Used for subcooled degree (SC = Tc – Tl) control during heating operation and cancellation of hot start (34°C) control. | |||
| Gas pipe thermistor | Tg | R3T (Th3) | Used for subcooled degree (SH = Tg – Tl) control in cooling operation. | |||
| Components of outdoor unit | A | Inverter compressor | INV | (MC1) | Used to conduct the capacity control (constant Te control in cooling, constant Tc control in heating) with inverter. | |
| B | STD compressor | STD | (MC2) | Used to conduct the capacity control with compressor using commercial power supply and inverter compressor (delayed start). | ||
| C | Receiver | — | — | Making constant supply of liquid refrigerant to liquid receiver and evaporator (expansion valve). Storing excessive refrigerant | ||
| D | Accumulator | — | — | Gas-liquid separator avoiding direct suction of liquid refrigerant to compressor. | ||
| E | Outdoor unit heat exchanger | — | — | Working as condenser in cooling operation and as evaporator in heating operation (air-cooled) | ||
| F | Outdoor unit electronic expansion valve | — | Y1E (20E) | Controlling so as to keep superheated degree (SH = Ts – Te) constant (basically 5°C) | ||
| G | Hot gas bypass solenoid valve | — | Y2S (20RP) | Used for pressure equalizing and low-pressure protection in no operation. | ||
| H | Injection solenoid valve | — | Y3S Y4S (20RT) | Conducts protection control with discharge pipe temperature (Tdi, Tds) and discharge superheated degree (Tdi, Tds – Tc) | ||
| I | Check valve | — | — | Prevents refrigerant from backword flow in operation only with inverter compressor. (Prevention of standard compressor start with deferential pressure) | ||
| J | Four way valve | — | Y1R (20S) | Making selection of cooling / heating cycle (energized coil for heating) | ||
| Components of indoor unit | K | Indoor unit heat exchanger | — | — | Heat exchanger works as evaporator in cooling operation and as condenser in heating operation. (Air cooled type) | |
| L | Indoor unit electronic expansion valve | — | Y1E (20E) | Used for superheated degree (SH = Tg – Tl) control in cooling operation, and for subcooled degree (SC = Tc – Tl) control during heating operation. Avoiding liquid collection, by setting the valve as minute opening (240 pls) in heating thermostat-off (when compressor is on). |
