Installing The Refrigerant Piping; Precautions For Devices That Use R410A Refrigerant - Mitsubishi Electric PUZ-HA NHA5 Série Manuel D'installation

4. Installing the refrigerant piping

45˚± 2˚
Flare cutting dimensions
Flare nut tightening torque
A (Fig. 4-1)
Flare dimensions
Copper pipe O.D.
øA dimensions
(mm) (inch) (mm)
ø6.35 1/4" 8.7 - 9.1
ø9.5 3/8" 1.8 - 13.
ø1.7 1/" 16. - 16.6
ø15.88 5/8" 19.3 - 19.7
B (Fig. 4-1)
Copper pipe O.D. Flare nut O.D.
(mm) (inch) (mm)
ø6.35 1/4" 17
ø9.5 3/8" 
ø1.7 1/" 6
ø15.88 5/8" 9
Front piping cover
Piping cover
Stop valve
Service panel
Bend radius : 100 mm, 3-15/16 inch-150 mm, 5-27/32 inch
Liquid pipe
A
Gas pipe
B
Insulation
C
Taping
D
Fig. 4-1
(inch)
Fig. 4-2
(inch)
11/3 - 3/64
1/ - 33/64
41/64 - 1/3
49/64 - 5/3
Tightening torque
(inch) (N·m)
43/64 14 - 18 10 - 13
7/8 34 - 4 5 - 30
1 - 3/64 49 - 61 35 - 44
1 - 9/64 68 - 8 49 - 59
Fig. 4-3

4.1. Precautions for devices that use R410A refrigerant

• Refer to page 3 for precautions not included below on using air condition-
ers with R410A refrigerant.
• Use ester oil, ether oil, alkylbenzene oil (small amount) as the refrigeration
oil applied to the flared sections.
• Use C1220 copper phosphorus, for copper and copper alloy seamless
pipes, to connect the refrigerant pipes. Use refrigerant pipes with the thick-
nesses specified in the table to the below. Make sure the insides of the
pipes are clean and do not contain any harmful contaminants such as sul-
furic compounds, oxidants, debris, or dust.
Warning:
When installing or relocating, or servicing the air conditioner, use only the
specified refrigerant (R410A) to charge the refrigerant lines. Do not mix it with
any other refrigerant and do not allow air to remain in the lines.
If air is mixed with the refrigerant, then it can be the cause of abnormal high
pressure in the refrigerant line, and may result in an explosion and other haz-
ards.
The use of any refrigerant other than that specified for the system will cause
mechanical failure or system malfunction or unit breakdown. In the worst
case, this could lead to a serious impediment to securing product safety.
Liquid pipe
Gas pipe
• Do not use pipes thinner than those specified above.
4.2. Connecting pipes (Fig. 4-1, Fig. 4-2)
When commercially available copper pipes are used, insulate both the liquid and
gas pipes separately with commercially available insulation materials (heat-resis-
tant to 100°C, 1°F or more, thickness of 1 mm, 1/ inch or more). (Fig. 4-1)
• The indoor parts of the drain pipe should be wrapped with polyethylene foam
insulation materials (specific gravity of 0.03, thickness of 9 mm, 3/64 inch or
more).
[Fig. 4-]
• Apply thin layer of refrigerant oil to pipe and joint seating surface before tighten-
ing flare nut. A
• Use two wrenches to tighten piping connections. B
• Use leak detector or soapy water to check for gas leaks after connections are
completed.
• Apply refrigerating machine oil over the entire flare seat surface. C
• Use the flare nuts for the following pipe size. D
Gas side Pipe size (mm, inch)
Liquid side Pipe size (mm, inch)
*1: The flare nut is attached to its pipe.
*: The flare nut is in the outdoor unit accessory.
Do not use the flare nut attached. If it is used, a gas leakage or even a pipe ex-
traction may occur.
(ft·lbs)
• When bending the pipes, be careful not to break them. Bend radii of 100 mm,
3-15/16 inch to 150 mm, 5-7/3 inch are sufficient.
• Make sure the pipes do not contact the compressor. Abnormal noise or vibration
may result.
1 Pipes must be connected starting from the indoor unit.
Flare nuts must be tightened with a torque wrench.
2 Flare the liquid pipes and gas pipes and apply a thin layer of refrigeration oil
(Applied on site).
4.3. Refrigerant piping (Fig. 4-3)
Remove the service panel D (3 screws) and the front piping cover A ( screws) and rear
piping cover B ( screws:HA30, HA36) (4 screws:HA4).
1 Perform refrigerant piping connections for the indoor/outdoor unit when the out-
door unit's stop valve is completely closed.
2 Vacuum-purge air from the indoor unit and the connection piping.
3 After connecting the refrigerant pipes, check the connected pipes and the indoor
unit for gas leaks. (Refer to 4.4 Refrigerant pipe airtight testing method)
4 Vacuumize the refrigerant lines through the service port of the liquid stop valve
and then open the stop valves completely (for both the liquid and gas stop
valves). This will completely connect the refrigerant lines of the indoor and out-
door units.
• If the stop valves are left closed and the unit is operated, the compressor and
control valves will be damaged.
• Use a leak detector or soapy water to check for gas leaks at the pipe connec-
tion sections of the outdoor unit.
• Do not use the refrigerant from the unit to purge air from the refrigerant lines.
• After the valve work is completed, tighten the valve caps to the correct torque:
0 to 5 N·m, 14 to 18 ft·lbs (00 to 50 kgf·cm).
Failure to replace and tighten the caps may result in refrigerant leakage. In
addition, do not damage the insides of the valve caps as they act as a seal to
prevent refrigerant leakage.
5 Use sealant to seal the ends of the thermal insulation around the pipe connec-
tion sections to prevent water from entering the thermal insulation.
ø9.5 mm, 3/8inch
thickness 0.8 mm, 1/3 inch
ø15.88 mm, 5/8 inch
thickness 1.0 mm, 3/64 inch
ø15.88, 5/8"
ø9.5, 3/8"
5