Refrigerant Pipe And Drain Pipe Specifications; Refrigerant Pipe And Drain Pipe Size; Connecting Refrigerant Pipes And Drain Pipes; Refrigerant Piping Work - Mitsubishi Electric PFFY-P-VLEM-E Installation Manual

5. Refrigerant pipe and drain pipe specifications

To avoid dew drops, provide sufficient antisweating and insulating work to the re-
frigerant and drain pipes.
When using commercially available refrigerant pipes, be sure to wind commer-
cially available insulating material (with a heat-resisting temperature of more than
100°C and thickness given below) onto both liquid and gas pipes.
Be also sure to wind commercially available insulating material (with a form
polyethylene's specific gravity of 0.03 and thickness given below) onto all pipes
which pass through rooms.

5.1. Refrigerant pipe and drain pipe size

[Fig. 5.1.1] (P.3)
A Flare cutting dimensions
B Refrigerant pipe sizes & Flare nut tightening torque
C Apply refrigerating machine oil over the entire flare seat surface
A Flare cutting dimensions
Copper pipe O.D. (mm)
B Refrigerant pipe sizes & Flare nut tightening torque
Liquid pipe
Tightening
Pipe size
P20/25/32/40 ODø6.35 (1/4") 14 – 18
P50 ODø6.35 (1/4") 34 – 42
P63 ODø9.52 (3/8") 34 – 42
* Use the provided flare nut for the following pipes: Liquid pipe and gas pipe of P50.
[Fig. 5.1.2] (P.3)
A Refrigerant pipe flare connection (for gas): LP
B Refrigerant pipe flare connection (for liquid): HP
C Drain pan
E Hose (accessory) (External diameter ø27 (end ø20))
F Air filter

6. Connecting refrigerant pipes and drain pipes

6.1. Refrigerant piping work

This piping work must be done in accordance with the installation manual for the
outdoor unit.
• For constraints on pipe length and allowable difference of elevation, refer to
the outdoor unit manual.
• The method of pipe connection is flare connection.
Cautions on refrigerant piping
s s s s s Be sure to use non-oxidative brazing for brazing to ensure that no for-
eign matter or moisture enter into the pipe.
s s s s s Be sure to apply refrigerating machine oil over the flare connection seat-
ing surface and tighten the connection using a double spanner.
Warning:
When installing and moving the unit, do not charge it with refrigerant other
than the refrigerant specified on the unit.
- Mixing of a different refrigerant, air, etc. may cause the refrigerant cycle to mal-
function and result in severe damage.
Caution:
• Use refrigerant piping made of C1220 (Cu-DHP) phosphorus deoxidized
copper as specified in the JIS H3300 "Copper and copper alloy seamless
pipes and tubes". In addition, be sure that the inner and outer surfaces of
the pipes are clean and free of hazardous sulphur, oxides, dust/dirt, shav-
ing particles, oils, moisture, or any other contaminant.
• Never use existing refrigerant piping.
- The large amount of chlorine in conventional refrigerant and refrigerator oil
in the existing piping will cause the new refrigerant to deteriorate.
• Store the piping to be used during installation indoors and keep both
ends of the piping sealed until just before brazing.
- If dust, dirt, or water gets into the refrigerant cycle, the oil will deteriorate and
the compressor may fail.
8
ø6.35
ø9.52
ø12.7
ø15.88
R410A
Gas pipe
Tightening
torque torque
Pipe size
(N·m) (N·m)
ODø12.7 (1/2") 49 – 61
ODø12.7 (1/2") 68 – 82
ODø15.88 (5/8") 68 – 82
D Stainer
G Electrical part box
1 Select the thickness of insulating material by pipe size.
Pipe size
6.4 mm to 25.4 mm
28.6 mm to 38.1 mm
2 If the unit is used on the highest story of a building and under conditions of
high temperature and humidity, it is necessary to use pipe size and insulating
material's thickness more than those given in the table above.
3 If there are customer's specifications, simply follow them.
Flare dimensions øA dimensions (mm)
R407C or R22
Liquid pipe
Tightening
torque
Pipe size Pipe size
(N·m)
ODø6.35 (1/4") 14 – 18 ODø12.7 (1/2")
ODø9.52 (3/8") 34 – 42* ODø15.88 (5/8")
ODø9.52 (3/8") 34 – 42 ODø15.88 (5/8")
• Use Suniso 4GS or 3GS (small amount) refrigerator oil to coat the flare
and flange connection part. (For models using R22)
• Use ester oil, ether oil or alkylbenzene (small amount) as the refrigerator
oil to coat flares and flange connections. (For models using R410A or
R407C)
- The refrigerant used in the unit is highly hygroscopic and mixes with water
and will degrade the refrigerator oil.

6.2. Drain piping work

1. Ensure that the drain piping is downward (pitch of more than 1/100) to the
outdoor (discharge) side. Do not provide any trap or irregularity on the way.
2. Ensure that any cross-wise drain piping is less than 20 m (excluding the differ-
ence of elevation). If the drain piping is long, provide metal braces to prevent it
from waving. Never provide any air vent pipe. Otherwise drain may be ejected.
3. Put the supplied strainer at the bottom of the drain pan on the side of the body
frame, and connect the supplied drain hose to the end connection. Tighten this
end connection using the supplied hose hand.
4. Use a VP30 pipe or equivalent for collecting pipe if it is needed, and pipe it
giving a downward pitch of more than 1/100.
5. Provide sufficient insulation just as for refrigerant piping.
[Fig. 6.2.1] (P.3)
A Indoor unit
C Drain pan
E Drain hose (accessory)
Caution:
Pipe the drain piping to ensure that it discharges drain, and insulate it to
prevent dew condensation. A failure to the piping work may cause water
leakage and so wet your property.
Insulating material's thickness
More than 10 mm
More than 15 mm
8.7 – 9.1
12.8 – 13.2
16.2 – 16.6
19.3 – 19.7
Flare nut O.D.
Gas pipe
Tightening Liquid
torque pipe
(N·m) (mm)
49 – 61 17
68 – 82* 22
68 – 82 22
B Strainer (accessory)
D Hose band (accessory)
Gas
pipe
(mm)
27
29
29