Panasonic U-4LE1E5 Service Manual page 37

3. Recovering Refrigerant
3-2-1. Cooling operation (for all units)
(1) Short-circuit the TEST pin (CN-TEST) on the outdoor control PCB.
(2) Let the unit operate for a while, then check if it is running in Cooling mode or Heating mode by touching the gas
line with your finger. If it is running in Heating mode, follow the instructions given in (3) through (5).
Cooling mode : low temperature (lower than 20°C)
Heating mode : high temperature (higher than 60°C)
CAUTION
(3) If the unit is in Heating mode, release the short-circuit across the test run pins on the outdoor control PCB of
the main unit. Then short-circuit the STOP pin (CN-STOP) to stop operation of the unit.
(4) Short-circuit the MODE pin (CN-MODE) on the outdoor control PCB.
* The 4-way valve will not change at this moment; rather, it changes just before start of operation. (It is difficult
to confirm the change by listening for the sound.)
(5) Short-circuit the TEST pin (CN-TEST) on the outdoor control PCB. Let the unit operate for a while, then check if it is
in Cooling mode by carefully touching the gas line.
3-2-2. Refrigerant recovery procedures (A) (using ball valve near the indoor unit)
Cooling operation
Gas tube
Outdoor unit
Liquid tube
(1) If a ball valve with a service port has been provided near the indoor unit as shown in Fig. 2-3, follow the
instructions given in (2) through (6) below. If the service port is instead located in the outdoor side, follow the
instructions in "3-2-3. Refrigerant recovery procedures (B)."
(2) After running the unit in Cooling mode for about 5 minutes, fully close the liquid line ball valve.
(3) Run the unit in Cooling mode for 10 to 20 minutes more.
(4) Fully close the gas line service valve.
(5) Use hoses to connect the manifold gauge valves, refrigerant recovery unit, and refrigerant recovery cylinder
with each other. (Fig. 2-4) Do each connection quickly to prevent air from entering the tubing.
CAUTION
(6) Recover the remaining refrigerant from the indoor unit using the refrigerant recovery unit.
NOTE
To determine completion of refrigerant recovery, follow the instructions that came with the refrigerant recovery unit.
Be careful when touching the gas line since the tubing may be very hot (about
60°C) during Heating mode.
Ball valve
(field supply)
Service port
Remaining refrigerant may create internal pressure, therefore care should be
taken when connecting the hoses.
Outdoor Unit Repair Procedures
Indoor unit
Fig. 2-3
2 - 7
Mini VRF SYSTEM
2