Tube Refrigerant Recovery Control - Panasonic U-8MF2E8 Service Manual

7. Tube Refrigerant Recovery Control

This control is intended to recover refrigerant if refrigerant has accumulated somewhere in the tubing
when the units have been stopped for long periods, as well as to compensate for tubing thermal loss during heating
start, and is also used for oil recovery.
Special control : Tube Refrigerant Recovery Control features one of the functions of special control.
7-1. Start of Tube Refrigerant Recovery Control
When the microcomputer is initialized immediately after power-ON.
After warning output occurs
After a set amount of time has elapsed 60 minutes when all outdoor units are stopped.
7-2. Simplified Flow of Tube Refrigerant Recovery Control
Whole Process
Tube refrigerant recovery control shall be performed as the flow mentioned below.
(0) Stopped
(1) Tube refrigerant recovery control processing time *
(2) Post-processing time of tube refrigerant recovery control for 2 minutes or non stop operation
(3) Normal operation
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* Tube Refrigerant Recovery Control Process
Control function when the outdoor unit heat exchanger is acting as a condenser.
(when all units are in cooling mode or at start of mixed operation when the cooling load is high.)
Control time
Outdoor units
Electronic control valve
All Indoor Units Solenoid valve kit
Fan
* When the above operation is finished, normal operation starts at the horsepower determined by the indoor units
where thermostats are ON.
* When the horsepower of cooling thermostat ON still remains greater than that of heating thermostat ON during
control mentioned above, normal control is performed without stopping the compressor.
* When the horsepower of heating thermostat ON is getting greater than that of cooling thermostat ON during
control mentioned above, once stop the outdoor unit after completion of control.
Then change the heat exchanger acting as a condenser to an evaporator and resume the operation.
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2 minutes
All outdoor units operate at maximum horsepower.
Valves at all indoor units operate at a fixed pulse according to
the indoor unit capacity.
Valve kits at all indoor units operate in cooling mode (ON status).
Fan runs at the set fan speed depending on the indoor unit
operation mode.
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3WAY SYSTEM
Control Functions
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