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2
Mini VRF SYSTEM
Outdoor Unit Repair Procedures
6. Pumping Out Refrigerant from Outdoor Unit
To determine the completion of refrigerant recovery, follow the instructions that came with the refrigerant recovery
unit.
unit.
NOTE
Manifold
gauge
Lo
Hi
Connect from here to
refrigerant recovery unit
refrigerant recovery unit
Fig. 2-8
Low-pressure outlet port
(For ø7.94 mm connector)
(For ø7.94 mm connector)
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Mini VRF SYSTEM
Outdoor Unit Repair Procedures
(1)
(2)
(a) Compressor
(b) Unit
(1)
(2)
(3)
(4)
(5)
(6)
7-1. Compressor Trouble Diagnosis and Check Methods
Generally, compressor failures can be classified into the following categories.
Mechanical trouble
Electrical trouble
(A) Locking (intrusion of foreign objects, galling, etc.)
(B) Pressure rise failure (damaged valve, seal, bearing, or other component)
(C) Noise (damaged stator, rotor, valve, or other component)
(A) Coil burning
(B) Open circuit
(C) Insulation failure
(D) Short circuit
Failure diagnosis is based on the following remote controller displays: [H01], [H02], [H03] (Compressor : right side
when viewed from front). A judgment is made based on factors that include the following: coil resistance (varies
depending on the compressor), insulation resistance, current, leakage breaker operation, oil and refrigerant fouling,
odor, pressure, and noise.
when viewed from front). A judgment is made based on factors that include the following: coil resistance (varies
depending on the compressor), insulation resistance, current, leakage breaker operation, oil and refrigerant fouling,
odor, pressure, and noise.
Reference: Insulation resistance (Use a DC 500 V insulation resistance meter and measure the insulation
resistance between the electrified and non-electrified parts.)
Reference: Symptoms of motor burning
1. Ground fault results in breaker operation.
2. Short circuit results in different coil resistance at different phases.
3. Open circuit
7-2. Compressor Replacement
Follow the instructions in “7-4. Replacing the Compressor” and replace compressor in the failed unit.
Fully close the high- and low-pressure gauge valves on the manifold gauge, then stop the vacuum pump.
Disconnect the manifold gauge from the vacuum pump. Connect the manifold gauge to the refrigerant
cylinder. At this time, be careful that air does not enter the refrigerant tubing.
cylinder. At this time, be careful that air does not enter the refrigerant tubing.
Do not use the recovered refrigerant. Use a refrigerant cylinder that contains
new refrigerant.
new refrigerant.
Open the valve on the refrigerant cylinder. When charging with the amount of recovered refrigerant is
completed, or when charging with the amount of recovered refrigerant is not completed but no more
refrigerant will enter the unit, first turn the power OFF at the repaired outdoor unit, then remove the short
circuit at the AP pin (CN-AP). Then fully open all valves on the gas tube, and liquid tube.
completed, or when charging with the amount of recovered refrigerant is not completed but no more
refrigerant will enter the unit, first turn the power OFF at the repaired outdoor unit, then remove the short
circuit at the AP pin (CN-AP). Then fully open all valves on the gas tube, and liquid tube.
If charging with the amount of recovered refrigerant was not possible, fully close the high-pressure gauge
valve on the manifold gauge. Then, while the unit is operating in Cooling mode, open the low-pressure
gauge valve on the manifold gauge and charge with the designated amount of refrigerant.
valve on the manifold gauge. Then, while the unit is operating in Cooling mode, open the low-pressure
gauge valve on the manifold gauge and charge with the designated amount of refrigerant.
When charging with liquid refrigerant, add refrigerant a little at a time in order
to prevent liquid back-flow.
to prevent liquid back-flow.
Remove the manifold gauge.
* Minimum insulation resistance as required by generally accepted requirements is 1 M .
Min. 50 M (servicing part)
Min. 10 M (This is due to the presence of refrigerant, which decreases
the insulation resistance.)
the insulation resistance.)
CAUTION
CAUTION
7. Compressor
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Mini VRF SYSTEM
Outdoor Unit Repair Procedures
(7)
The connecting port includes a Schrader-type, push-to-release valve.
When disconnecting the hose, pressure will be applied from the refrigerant in
the outdoor unit.
When disconnecting the hose, pressure will be applied from the refrigerant in
the outdoor unit.
Follow the instructions in “7-3. Dry Core Cleaning” and perform dry core cleaning of the outdoor unit that failed.
CAUTION
(1)
(2)
(3)
(4)
(5)
(6)
(7)
(8)
(9)
(10)
(11)
(12)
(13)
(14)
(15)
(16)
(17)
7-3. Dry Core Cleaning
If burning or other failures occur repeatedly at compressor, in many cases the cause is acid, sludge, carbon, or
other substances that remain in the refrigeration cycle as the result of insufficient cleaning.
If, when the oil is inspected, there is an outdoor unit where the oil color phase is 4.0 or higher, or where a sharp
odor is present, carry out all steps below to perform dry core cleaning.
* The operating pressure is approximately 1.5 times higher than with R22 or R407C. Therefore use R410A dry
cores.
If burning or other failures occur repeatedly at compressor, in many cases the cause is acid, sludge, carbon, or
other substances that remain in the refrigeration cycle as the result of insufficient cleaning.
If, when the oil is inspected, there is an outdoor unit where the oil color phase is 4.0 or higher, or where a sharp
odor is present, carry out all steps below to perform dry core cleaning.
* The operating pressure is approximately 1.5 times higher than with R22 or R407C. Therefore use R410A dry
cores.
Refer to “Refrigerant recovery procedures (B): for indoor unit with no ball valve” under “3-2. Refrigerant
Recovery Procedures (Indoor Unit).” Perform pump-down of the refrigerant from all indoor units and inter-unit
tubing to the outdoor unit side.
Recovery Procedures (Indoor Unit).” Perform pump-down of the refrigerant from all indoor units and inter-unit
tubing to the outdoor unit side.
Cut the liquid tube at all outdoor units where dry cores will be attached, then attach the dry cores and ball
valves as shown in Fig. 2-9.
valves as shown in Fig. 2-9.
Operate outdoor unit (in either Heating or Cooling mode).
Fully close the liquid tube valve and ball valve at the outdoor unit where dry cores will be attached.
Stop operation of outdoor unit.
Connect a refrigerant recovery device to the liquid tube service port (Schrader-type valve) on the outdoor unit
where dry cores will be attached. Recover the refrigerant that is in the tubing. At this time, be careful that air
does not enter the tubing.
where dry cores will be attached. Recover the refrigerant that is in the tubing. At this time, be careful that air
does not enter the tubing.
The connecting port includes a Schrader-type, push-to-release valve.
When connecting the hose, internal pressure will be applied from the remaining
refrigerant in the inter-unit tubing. To determine when refrigerant recovery has
been completed, follow the instructions that came with the refrigerant recovery
device.
When connecting the hose, internal pressure will be applied from the remaining
refrigerant in the inter-unit tubing. To determine when refrigerant recovery has
been completed, follow the instructions that came with the refrigerant recovery
device.
As shown in Fig. 2-9, disconnect the tube that runs from the liquid tube valve to the ball valve on the outdoor
unit where dry cores will be attached. Then attach the dry cores.
unit where dry cores will be attached. Then attach the dry cores.
At all outdoor units where dry cores are attached, pressurize with 3.80 MPa of nitrogen from the liquid tube
service port and check for leaks.
service port and check for leaks.
After draining all nitrogen from the tubing, apply vacuum from the liquid tube service port to the outdoor unit
where dry cores are attached until the pressure is –101 kPa {–755 mm Hg, 5 Torr} or less.
where dry cores are attached until the pressure is –101 kPa {–755 mm Hg, 5 Torr} or less.
Fully open the liquid tube valve and ball valve on the outdoor unit where dry cores are attached.
Operate the outdoor unit for approximately 3 hours (in either Heating or Cooling mode).
Follow the above procedure, and replace all dry cores with new dry cores.
Operate all outdoor units for approximately 20 minutes (in either Heating or Cooling mode).
Follow the instructions in “2. Discharging Oil in Compressor” and drain a small amount of the oil from the oil
separators of all outdoor units where dry cores are attached. Check the color phase, odor, and other
characteristics.
separators of all outdoor units where dry cores are attached. Check the color phase, odor, and other
characteristics.
If the results show that dry core cleaning is still necessary (for example, a color phase of 4.0 or higher), return
to Step 13 and repeat until the results are normal (including a color phase of 3.5 or less).
to Step 13 and repeat until the results are normal (including a color phase of 3.5 or less).
Perform another dry core replacement after approximately 30 hours of system
operation.
operation.
Fully close the liquid tube valve and ball valve on the outdoor unit where dry cores are attached.
Connect a refrigerant recovery device to the liquid tube service port (Schrader-type valve) on the outdoor unit
where dry cores are attached. Recover the refrigerant that is in the tubing. At this time, be careful that air does
not enter the tubing.
where dry cores are attached. Recover the refrigerant that is in the tubing. At this time, be careful that air does
not enter the tubing.
CAUTION
CAUTION
7. Compressor
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Mini VRF SYSTEM
Outdoor Unit Repair Procedures
7. Compressor
(18)
(19)
(20)
(21)
(1)
(2)
(3)
(4)
(5)
(6)
(7)
(8)
(9)
Remove dry cores. Connect the tube that runs
from the liquid tube valve to the ball valve.
from the liquid tube valve to the ball valve.
At the outdoor unit where dry cores were removed,
pressurize with 3.80 MPa of nitrogen from the liquid
tube service port and check for leaks.
pressurize with 3.80 MPa of nitrogen from the liquid
tube service port and check for leaks.
After draining all nitrogen from the tubing, apply
vacuum to the outdoor unit where dry cores were
removed until the pressure is –101 kPa {–755 mm
Hg, 5 Torr} or less using the liquid tube service
port.
vacuum to the outdoor unit where dry cores were
removed until the pressure is –101 kPa {–755 mm
Hg, 5 Torr} or less using the liquid tube service
port.
7-4. Replacing the Compressor
When removing and installing compressors, use
sufficient caution to ensure that water or other
substances do not enter the refrigerant tubing system.
sufficient caution to ensure that water or other
substances do not enter the refrigerant tubing system.
7-4-1. Replacing the compressor
(A) Replacing the inverter compressor
(Compressor 1 on remote controller alarm display)
(Compressor 1 on remote controller alarm display)
Removal
Connect a manifold gauge to the high- and low-
pressure outlet ports at the outdoor unit where the
compressor will be replaced. Connect the manifold
gauge to a nitrogen cylinder and perform nitrogen
replacement.
pressure outlet ports at the outdoor unit where the
compressor will be replaced. Connect the manifold
gauge to a nitrogen cylinder and perform nitrogen
replacement.
Follow the procedure for removing panels, and
remove the front panel, the right lower panel, and
the electrical component box cover. (Fig. 2-10)
remove the front panel, the right lower panel, and
the electrical component box cover. (Fig. 2-10)
Follow the refrigerant work procedure and recover
the refrigerant.
the refrigerant.
Remove the acoustic material that surrounds the
compressor (3 layers).
compressor (3 layers).
Remove the cap from the compressor terminal
plate. Disconnect the power terminal and internal
terminal.
plate. Disconnect the power terminal and internal
terminal.
Remove the crankcase heater.
Remove the 3 flange washers that are attached to
the compressor legs as shown in Fig. 2-11.
Remove the 3 flange washers that are attached to
the compressor legs as shown in Fig. 2-11.
Prepare to disconnect the 2 welded locations shown
in Fig. 2-11. Protect the sensors and the surrounding
plates, rubber, lead wires, clamps, and other items.
in Fig. 2-11. Protect the sensors and the surrounding
plates, rubber, lead wires, clamps, and other items.
Disconnect the 2 welded locations shown in Fig. 2-11.
Tilt the compressor toward you slightly. Lift it off of
the bolt at the rear of the compressor, then pull the
compressor toward you.
the bolt at the rear of the compressor, then pull the
compressor toward you.
Refer to the “Charging additional refrigerant” items.
Charge with an amount of refrigerant equal to the
amount that was recovered.
Charge with an amount of refrigerant equal to the
amount that was recovered.
Liquid tube
valve
valve
Liquid tube
Outdoor unit
service port
Dry core
Ball valve
Fig. 2-9
Fig. 2-10
Fig. 2-11
Front panel
Cover A
Acoustic material
Crankcase heater
Washer-with-collar (3 locations)
Cushioning rubber
(3 locations)
Welding locations to disconnect (2)
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