Processes and Functions
6
TD831077
VI - 7
5. Solenoid Valve Control
(8) PC oil valve control (OILP), SC oil valve control (OILS)
There is no oil sensor in the AC compressor due to cross oil control. As a result, no oil valve is attached.
Oil is constantly returning to the AC compressor by passing through a capillary tube.
1 When self-separator oil recovery is performed
¶ The oil valve of the operating compressor not having enough oil is turned on.
2 When involved in inter-unit oil recovery control
¶ When supplying oil to other units: Both the PC oil valve and SC oil valve are turned off.
¶ When oil is received from other units: The oil valve of the compressor not having enough oil is turned on.
3 Other items
¶ The oil valve for compressors that are stopped are turned off. However, both valves are turned on for five
minutes after the outdoor unit is stopped in order to obtain balanced pressure.
¶ The oil valve of the compressor not having enough oil is turned on, and the oil valve of the compressor
having enough oil is turned off.
¶ When the AC compressor is operating, the oil valve is turned off if there is enough oil in the corresponding
compressor.
¶ When the AC compressor is stopped, the oil valve of the compressor that is operating is turned on.
(9) 4-way valve control (20S)
1 During normal operation, 4-way valve control is turned off during cooling operation and turned on during
heating operation. (The output status for all outdoor units is the same.)
2 When an outdoor unit is stopped, the mode just before stopping is maintained.
6. Hot Gas Defrosting Control
¶ Hot gas defrosting using a normal cycle is performed.
¶ Defrosting is performing by using some discharge gas to bypass to the distributor of the outdoor heat exchanger.
6-1. Frost detection
(1) Frost detection is not performed for five minutes from the start of operation.
(2) Frost detection conditions = Condition 1 or Condition 2
Condition 1 = L2 line or below for four continuous minutes is detected twice
Condition 2 = L1 line or below detected for a total of 60 minutes
–25
–23
–10
The frost detection area is
located under the thick lines
L2
L1
–3
–21.4
–8
–1
6
10 External temperature °C
1814_M_I
Heat exchange liquid temperature °C
Defrosting operation
end temperature
(The end temperature
is different from the
above detection
temperature.)
Fig. 1
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