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2
Mini VRF SYSTEM
Outdoor Unit Repair Procedures
3. Recovering Refrigerant
The following equipment and tools are required:
Jumper wire with clips, adjustable wrench, set of manifold gauge valves specially designed for refrigerant R410A
only, vacuum pump, refrigerant recovery unit, pre-purged refrigerant cylinder for recovery (air already evacuated),
and hex wrench (4 mm for liquid tube and 5 mm for gas tube).
only, vacuum pump, refrigerant recovery unit, pre-purged refrigerant cylinder for recovery (air already evacuated),
and hex wrench (4 mm for liquid tube and 5 mm for gas tube).
3-1. Refrigerant Recovery Procedures (From Outdoor Unit)
(1) Turn off the power of the outdoor unit beforehand (at power mains).
(2) Fully close each service valve on the gas line and liquid line of the outdoor unit.
(3) Connect the outdoor unit’s high-pressure and low-pressure outlet ports with the Hi and Lo sides of the
manifold gauge valves using hoses. (Fig. 2-2 )
manifold gauge valves using hoses. (Fig. 2-2 )
The remaining refrigerant in the outdoor unit may create internal pressure.
Before connecting hoses, be sure to confirm that each of the manifold gauge
valves is tightly closed. Note that the connection ports employ Schrader-type,
press-to-release valves.
Before connecting hoses, be sure to confirm that each of the manifold gauge
valves is tightly closed. Note that the connection ports employ Schrader-type,
press-to-release valves.
For detailed procedures such as connecting the refrigerant recovery unit
with the recovery cylinder and methods used for recovery, follow the specific
instructions that came with the refrigerant recovery unit.
with the recovery cylinder and methods used for recovery, follow the specific
instructions that came with the refrigerant recovery unit.
By short-circuiting the AP pins, each electronic expansion valve in the
outdoor unit is forcibly opened as soon as power comes on, which releases
all remaining refrigerant into the recovery cylinder. Since neglecting this
procedure may leave some refrigerant in the system, it is important that you
carry out this step.
outdoor unit is forcibly opened as soon as power comes on, which releases
all remaining refrigerant into the recovery cylinder. Since neglecting this
procedure may leave some refrigerant in the system, it is important that you
carry out this step.
To determine the completion of refrigerant recovery, follow the instructions
that came with the refrigerant recovery unit.
that came with the refrigerant recovery unit.
CAUTION
CAUTION
CAUTION
CAUTION
Fig. 2-2
Refrigerant recovery cylinder
Refrigerant
recovery unit
recovery unit
Manifold
gauge
Low-pressure outlet port
(For ø7.94 mm connector)
(For ø7.94 mm connector)
Lo
Hi
(4) Connect the manifold gauge valves, refrigerant recovery unit, and recovery cylinder using hoses.
To avoid the entry of air into the refrigerant tubing, carry out this connection work carefully.
To avoid the entry of air into the refrigerant tubing, carry out this connection work carefully.
(5) Locate the AP pins on the control PCB in the outdoor unit and short them using the clips of the jumper wire.
Then restore electrical power to the outdoor unit.
Then restore electrical power to the outdoor unit.
(6) Carry out refrigerant recovery.
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2
Mini VRF SYSTEM
Outdoor Unit Repair Procedures
3-2. Refrigerant Recovery Procedures (Indoor Unit)
The flowchart below shows the refrigerant recovery procedures you must follow when replacing or repairing the
indoor unit due to trouble in the refrigerant circuit.
The flowchart below shows the refrigerant recovery procedures you must follow when replacing or repairing the
indoor unit due to trouble in the refrigerant circuit.
* Service work performed on indoor units is done simultaneously using the service ports at the
liquid tube side and the gas tube side ball valves. Refer to each section in the “Installation
Instructions” on refrigerant charging, leak checking, and evacuation procedures.
liquid tube side and the gas tube side ball valves. Refer to each section in the “Installation
Instructions” on refrigerant charging, leak checking, and evacuation procedures.
START
3-2-1. Cooling operation (for all units)
Ball valve is provided in the indoor unit
Turn off all equipment in system
Replace or repair faulty unit
Check for leakage in repaired unit
Evacuate air from repaired unit
Open ball valve
Ready for operation
END
Charge refrigerant in repaired unit
(Amount of charge should equal that
recovered by refrigerant recovery unit)
Charge refrigerant in repaired unit *
(Amount of charge should equal that
recovered by refrigerant recovery unit)
3-2-3. Refrigerant recovery
procedures (2)
Turn off all equipment in system
Other indoor units can operate normally
Replace or repair faulty unit
Check for leakage in repaired unit *
Evacuate air from repaired unit *
Open ball valve
Ready for normal operation
END
END
Ready for normal operation
Open the ball valve
Evacuate air in repaired unit *
Check for leakage in repaired unit *
Replace or repair faulty unit
Charge refrigerant in repaired unit *
(Amount of charge should equal that
recovered by refrigerant recovery unit)
Change controllable number of indoor
units (including changes in group
control and integrated-control settings)
3-2-2. Refrigerant recovery
procedures (1)
When replacing or repairing a faulty
unit, let other normal indoor units run
(excluding indoor unit where refrigerant
is recovered)
power to refrigerant-recovered
indoor units independently
Modify power to permit turning off
Power can independently be turned off
for indoor unit where refrigerant is
recovered
Change controllable number of indoor
units (including changes in group
control and integrated-control settings)
NO
NO
NO
YES
YES
YES
3. Recovering Refrigerant
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2
Mini VRF SYSTEM
Outdoor Unit Repair Procedures
(1)
(2)
(3)
(4)
(5)
(1)
(2)
(3)
(4)
(5)
(6)
3-2-1. Cooling operation (for all units)
Short-circuit the TEST pin (CN-TEST) on the outdoor control PCB.
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).
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)
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.
the main unit. Then short-circuit the STOP pin (CN-STOP) to stop operation of the unit.
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.)
* 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.)
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.
in Cooling mode by carefully touching the gas line.
3-2-2. Refrigerant recovery procedures (A) (using ball valve near the indoor unit)
Fig. 2-3
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).”
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).”
After running the unit in Cooling mode for about 5 minutes, fully close the liquid line ball valve.
Run the unit in Cooling mode for 10 to 20 minutes more.
Fully close the gas line service valve.
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.
with each other. (Fig. 2-4) Do each connection quickly to prevent air from entering the tubing.
Remaining refrigerant may create internal pressure, therefore care should be
taken when connecting the hoses.
taken when connecting the hoses.
Recover the remaining refrigerant from the indoor unit using the refrigerant recovery unit.
To determine completion of refrigerant recovery, follow the instructions that came with the refrigerant recovery unit.
NOTE
Ball valve
(field supply)
Gas tube
Outdoor unit
Cooling operation
Indoor unit
Liquid tube
Service port
CAUTION
Be careful when touching the gas line since the tubing may be very hot (about
60°C) during Heating mode.
60°C) during Heating mode.
CAUTION
3. Recovering Refrigerant
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2
Mini VRF SYSTEM
Outdoor Unit Repair Procedures
Refrigerant
recovery unit
recovery unit
Manifold
gauge
Lo
Hi
Refrigerant
recovery cylinder
Ball valve
(field supply)
Gas tube
Outdoor unit
Indoor unit
Liquid tube
Service port
Fig. 2-4
3. Recovering Refrigerant
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