Panasonic U-4LE1E5 Service Manual page 37

3. Recovering Refrigerant
3-2-3. Refrigerant recovery procedures (B): for indoor unit with no ball valve
Refrigerant in all indoor units and the refrigerant tubing circuit must be pumped into the outdoor unit (referred to as
"pump down"). The maximum refrigerant storage capacity per a single outdoor unit is approx. 3.5 kg. Thus, in order
to collect all refrigerant from the system, a separate refrigerant recovery unit is necessary. Follow these procedures
to correctly perform pump down.
(1) Using hoses, connect the manifold gauge valves to both the high-pressure and low-pressure outlet ports of
the outdoor unit to be pumped down. Quickly connect each part to prevent air from entering the tubing.
(2) After running the unit in Cooling mode for about 5 minutes, fully close the liquid line valve of the outdoor unit to
be pumped down.
(3) When the high-pressure gauge reading shows 3.80 MPa or more (or the low-pressure gauge reading falls to 0.5
MPa or less), pull out the EXL2 connector (3P) (YEL) (CN-RC) on the control PCB of the outdoor unit, then
immediately close the gas line service valve.
* As soon as the EXL2 connector is pulled out, F24 alarm (abnormal sensor) immediately turns on and the
outdoor unit stops.
When pulling out the EXL2 connector, be sure to grasp the connector securely
with your fingers and never pull it directly by its wires. When any other connector
CAUTION
except the EXL2 is disconnected, the outdoor unit will not stop. Be sure to pull
out only the EXL2 connector as described.
(4) Turn off power to all equipment in the system. Then pull out the RC1 connector (4P) (BLU) (CN006) on the
outdoor control PCB in the outdoor unit for which pump down has been completed.
(5) Turn on power for all equipment in the system and let the outdoor unit run in Cooling mode.
* Because the test run pins on the outdoor control PCB of the unit have been short-circuited, all units start
Cooling mode operation 3 minutes after power ON.
(6) Using hoses with Schrader-type, push-to-release valves, connect the manifold gauge valves to the gas line
service port and the liquid line service port in the outdoor unit to undergo pump-down. (Fig. 2-5)
Remaining refrigerant in the system may cause internal pressure. Check that each
valve on the manifold gauge is tightly closed. A Schrader-type, push-to-release
CAUTION
valve is provided for each connection port.
(7) Use hoses to connect the manifold gauge valves, refrigerant recovery unit, and refrigerant recovery cylinder.
Quickly connect each part to prevent air from entering the tubing.
(8) Recover remaining refrigerant from
the inter-unit tubing and indoor units
using the refrigerant recovery unit.
NOTE
To determine the completion of
refrigerant recovery, follow the
instructions that came with the
refrigerant recovery unit.
Refrigerant
recovery unit
Refrigerant recovery cylinder
2 - 9
Outdoor Unit Repair Procedures
Low-pressure outlet port
(For ø7.94 mm connector)
Manifold
gauge
Lo Hi
Fig. 2-5
Mini VRF SYSTEM
2