Installing The Refrigerant Piping; Precautions For Devices That Use R410A Refrigerant - Mitsubishi Electric PUZ-A12 NHA7 Manuel D'installation

4. Installing the refrigerant piping

Fig. 4-1
A
A Flare cutting dimensions
B Flare nut tightening torque
Gas side Pipe size (mm, inch)
Liquid side Pipe size (mm, inch)
A (Fig. 4-1)
Flare dimensions
Copper pipe O.D.
øA dimensions
(mm) (inch) (mm)
ø6.35 1/4" 8.7 - 9.1
ø9.52 3/8" 12.8 - 13.2
ø12.7 1/2" 16.2 - 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
ø9.52 3/8" 22
ø12.7 1/2" 26
ø15.88 5/8" 29
A12, A18
D
D
A Front piping cover
B Piping cover
C Stop valve
D Service panel
E Bend radius : 100 mm, 3-15/16 inch-150 mm, 5-27/32 inch
Fig. 4-3
A
Liquid pipe
B
Gas pipe
C
Inslation
D
Taping
B
C
D
Fig. 4-2
A12, A18 A24 - A42
ø12.7, 1/2" ø15.88, 5/8"
ø6.35, 1/4" ø9.52, 3/8"
(inch)
11/32 - 23/64
1/2 - 33/64
41/64 - 21/32
49/64 - 25/32
Tightening torque
(inch) (N·m) (ft·lbs)
43/64 14 - 18 10 - 13
7/8 34 - 42 25 - 30
1 - 3/64 49 - 61 35 - 44
1 - 9/64 68 - 82 49 - 59
A24-A42
C
B
A
E

4.1. Precautions for devices that use R410A refrigerant

• Refer to page 3 for precautions not included below on using air conditioners
with R410A refrigerant.
• Use ester oil, ether oil, alkylbenzene oil (small amount) as the refrigeration
oil applied to the fl ared sections.
• Use C1220 copper phosphorus, for copper and copper alloy seamless pipes,
to connect the refrigerant pipes. Use refrigerant pipes with the thicknesses
specifi ed in the table to the below. Make sure the insides of the pipes are
clean and do not contain any harmful contaminants such as sulfuric com-
pounds, oxidants, debris, or dust.
Warning:
When installing or relocating, or servicing the air conditioner, use only the
specifi ed 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 pres-
sure in the refrigerant line, and may result in an explosion and other hazards.
The use of any refrigerant other than that specifi ed 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.
(inch)
Liquid pipe
thickness 0.8 mm, 1/32 inch
Gas pipe
thickness 0.8 mm, 1/32 inch
• Do not use pipes thinner than those specifi ed above.
4.2. Connecting pipes (Fig. 4-1) (Fig. 4-2)
When commercially available copper pipes are used, inslate both the liquid and
gas pipes separately with commercially available insulation materials (heat-resist-
ant to 100 °C, 212 °F or more, thickness of 12 mm, 1/2 inch or more). (Fig. 4-1)
• The indoor parts of the drain pipe should be wrapped with polyethylene foam insu-
lation materials (specifi c gravity of 0.03, thickness of 9 mm, 23/64 inch or more).
[Fig. 4-2]
• Apply thin layer of refrigerant oil to pipe and joint seating surface before tightening
fl are nut. A
• Use 2 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 fl are seat surface. C
• Use the fl are nuts for the following pipe size. D
Notes:
1. The fl are nut is attached to its pipe.
2. The fl are nut is in the outdoor unit accessory.
Do not use the fl are nut attached. If it is used, a gas leakage or even a pipe
extraction may occur.
• When bending the pipes, be careful not to break them. Bend radii of 100 mm,
3-15/16 inch to 150 mm, 5-27/32 inch are suffi cient.
• 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).
Warning:
When installing the unit, securely connect the refrigerant pipes before starting
the compressor.
4.3. Refrigerant piping (Fig. 4-3)
■
For A12, A18
Remove the service panel D (2 screws).
■
For A24-A42
Remove the service panel D (3 screws) and the front piping cover A (2 screws)
and rear piping cover B (2 screws:PUZ(Y)-A24, A30NHA7) (4 screws:PUZ(Y)-A36,
A42NKA7).
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 outdoor 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 connection
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:
20 to 25 N·m, 14 to 18 ft·lbs (200 to 250 kgf·cm).
Failure to replace and tighten the caps may result in refrigerant leakage. In addi-
tion, 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 connection
sections to prevent water from entering the thermal insulation.
A12, A18
ø6.35 mm, 1/4inch ø9.52 mm, 3/8 inch
thickness 0.8 mm, 1/32 inch
ø12.7 mm, 1/2 inch ø15.88 mm, 5/8 inch
thickness 1.0 mm, 3/64 inch
A24-A42
5