J Series Special Operations
1. Pressure Balance Control
The pressure balance operation is performed to balance the pressure inside the refrigerant circuit during any of the following operating transitions:
- Cooling to heating
- Cooling to stopping
- Heating to cooling
- Heating to stopping
2. Oil Recovery Operation
Purpose
Refrigerant lubricant can be transported to indoor units and connection piping together with the refrigerant as compressor operating time increases. Oil recovery returns this oil to the outdoor unit at defined intervals to help prevent compressor damage caused by insufficient lubrication.
Automatic oil recovery timing
| Condition | Oil recovery timing |
|---|---|
| First oil recovery after power is turned on | 1 hour |
| Cooling mode | At intervals of 3 hours |
| Heating mode | At intervals of 12 hours |
Forced oil recovery
Oil recovery can be initiated using the forced oil recovery DIP switch. Change the switch from OFF to ON or ON to OFF and keep it in the changed position for more than 10 seconds.
Compressor operation during oil recovery
| Oil recovery operation time | 210 seconds |
| Compressor function frequency | 50 Hz (may fluctuate due to protection control) |
| Outdoor fan | Fan speed is determined by outdoor temperature and heat exchanger middle temperature. |
When oil recovery starts from cooling operation, the compressor does not stop before entering oil recovery operation. When oil recovery is completed, the compressor stops once and then shifts to normal operation.
3. Defrosting Operation
Purpose
Defrost operation removes frost formed on the outdoor heat exchanger surface. This prevents a decline in heat transfer efficiency and supports efficient heating operation.
Defrost start conditions
Defrosting starts when all of the following conditions are satisfied:
- Outdoor unit operating mode is heating.
- Integrated compressor operating time has reached 40 minutes or longer.
- The operating outdoor heat exchanger temperature has become less than -10°C.
Defrost end conditions
Defrosting ends when any one of the following conditions is satisfied:
- The operating heat exchanger temperature exceeds 10°C.
- 10 minutes or longer have elapsed since defrosting started.
- The operating mode changes from heating to cooling.
4. Crankcase Heater Operation
The crankcase heater keeps the compressor temperature at or above ambient temperature while the compressor is stopped. This helps protect the compressor from startup failure caused by refrigerant remaining inside the compressor.
Starting conditions
The crankcase heater starts under either of the following conditions:
- The heat exchanger middle temperature thermistor falls below 38°C after 3 minutes from power-on, provided the compressor has not started since power was applied.
- The heat exchanger middle temperature thermistor falls below 38°C after the compressor has been stopped for more than 30 minutes following operation.
Release conditions
The crankcase heater is released when either of the following occurs:
- The heat exchanger middle temperature thermistor rises above 42°C.
- The compressor is turned ON.