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Mini VRF SYSTEM
Outdoor Unit Repair Procedures
3
7.
Pumping Out Refrigerant from Outdoor Unit
The hoses may be subject to internal pressure from the refrigerant inside the outdoor
unit. Check that the manifold gauge valves are fully closed beforehand. A Schrader-
type push-to-release valve is provided at each connection port.
For the method used for additional oil charging after compressor replacement, see Section “6-1. If Refrigerant Has
Already Been Charged to Outdoor Unit.”
Required equipment and tools: Jumper wire with clips, adjustable wrench, set of manifold gauge valves for the
refrigerant R32, refrigerant recovery unit, pre-purged refrigerant cylinder for
recovery, flathead screwdriver, and outdoor unit maintenance remote controller.
This work is performed in order to collect the refrigerant from an outdoor unit where repairs (other than compressor
replacement) will be performed into other outdoor units and indoor units, and the refrigerant tubing.
7-1. If Remote Controller is Used for Maintenance of Outdoor Unit
(1) Connect the manifold gauge valves at the Lo side to the low-pressure outlet port of the outdoor unit.
Also connect the refrigerant recovery cylinder at the liquid tube service port (Schrader-type push-to-release
valve). Perform the connection work quickly so that no air is allowed to enter them. (Fig. 10)
* Connecting the refrigerant recovery cylinder is done to prevent pressure from rising excessively during backup
operation by recovering the refrigerant from the outdoor unit to be repaired.
(Measure the weight of the refrigerant and cylinder itself beforehand and provide sufficient safety measures,
such as installing a high-pressure cutout in the circuit.)
(2) Connect the outdoor unit maintenance remote controller to the CN-RC connector (3P) (BLU) on the outdoor
unit control PCB. Then start a test run of all units. (Press and hold the
(CHECK) button for 4 seconds or
longer.)
(3) Use the outdoor unit maintenance remote controller to check the operating status of the indoor units. Check
that all units are operating in Heating mode. For details concerning operation of the outdoor unit maintenance
remote controller, see Section “Outdoor unit maintenance remote controller”. It is also possible to check the
operating conditions either in cooling or heating mode by touching the gas tube.
Cooling mode: low temperature (20℃ or lower)
Heating mode: high temperature (60℃ or higher)
The gas tubing becomes hot (60°C or higher) in heating. Be careful so as not to be
burnt when touching the tubing.
(4) Then slowly close the liquid tube service valve.
(5) When the low pressure at the outdoor unit to be repaired reaches 0.5 MPa or below, press the ON/OFF button
on the outdoor unit maintenance remote controller to stop all the units. Then immediately fully close the gas
tube valve on that outdoor unit.
While closing the valves, the rise in discharge temperature or another factor may cause
a protective device to activate, stopping the operation of the outdoor unit. If this occurs,
immediately fully close the gas tube valve on the outdoor unit to be repaired.
(6) Connect the high-pressure gauge side of the manifold gauge to the high-pressure outlet port on the outdoor
unit, and connect the manifold gauge to the refrigerant recovery device. Be sure that no air enters the tubing at
this time.
6-3. Charging Additional Compressor Oil (after replacing compressor)
The rated amount of compressors as given below:
When replacing a faulty compressor, be sure to first measure the weight of the compressor.
If the surplus oil is removed along with the compressor, add the same amount of new oil.
For example:
Additional oil to be charged: 23.4 kg (removed compressor weight) – 23.2 kg (new compressor weight) = 0.2 kg ≒ 0.2 L
* If the result is a negative weight (removed compressor weight is less than the rated weight), it is not necessary
to discharge the extra oil from the system.
The oil absorbs moisture readily. This work must be completed quickly.
Fig. 9
Rated Capacity Compressor model Q'ty Weight (OIL IN) [kg]
9VD650XAA21
9VD650XAA21
8HP
10HP
23.2
23.2
1
1
6-2. If Outdoor Unit Has Not Been Charged with Refrigerant
When a compressor has been replaced or in any other case where the outdoor unit has not been charged with
refrigerant, first charge with refrigerant then follow the instructions in “6-1. If Refrigerant Has Already Been Charged
to Outdoor Unit” and charge with oil.
Or, alternatively, follow the procedure below.
(1) Connect a tube to the oil outlet port on the outdoor unit to be charged with oil. Insert the other end of the tube into
the oil container.
(2) Follow the instructions in “5. Evacuating System,” and apply vacuum to the outdoor unit to be charged with oil.
When this is done, oil is charged into the outdoor unit through the oil outlet port.
(3) When the unit has been charged with the designated amount of oil, stop the vacuum pump.
CAUTION
Gas tube service port
(for ø7.94mm-dia connector)
High-pressure outlet port
(for ø7.94mm-dia connector)
Low-pressure outlet port
(for ø7.94mm-dia connector)
Liquid tube service port
(for ø7.94mm-dia connector)
Manifold gauge
Lo Hi
Vacuum pump
Oil
CAUTION
CAUTION
CAUTION
SM830289-01_欧州向け R32 mini VRF 8,10HP SM&TRSM.indb 15SM830289-01_欧州向け R32 mini VRF 8,10HP SM&TRSM.indb 15 2021/05/07 10:12:122021/05/07 10:12:12
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