Refrigerant Pipe And Drain Pipe Specifications; Refrigerant Pipe, Drain Pipe And Filling Port; Request For Refrigerant Piping Connection; Connecting Refrigerant Pipes And Drain Pipes - Mitsubishi Electric CITY MULTI PEFY-P-NMHU-E2 Installation Manual

6. Refrigerant pipe and drain pipe specifications
To avoid dew drops, provide sufficient antisweating and insulating work to the
refrigerant 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 [212 °F] 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.
1 Select the thickness of insulating material by pipe size.
Pipe size
6.4 mm to 25.4 mm [1/4 in to 1 in]
28.6 mm to 38.1 mm [1-1/8 in to 1-1/2 in]
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.
6.1. Refrigerant pipe specifications
Refrigerant pipe sizes
Liquid pipe
Pipe size
P15·18 O.D. ø6.35 mm (1/4")
P24·27·30·36·48·54 O.D. ø9.52 mm (3/8")
6.2. Refrigerant pipe, drain pipe and filling
port
[Fig. 6.2.1] (P.2)
A Air inlet
C Refrigerant piping (gas)
E Drain outlet

7. Connecting refrigerant pipes and drain pipes

7.1. Refrigerant piping work
This piping work must be done in accordance with the installation manuals for
both outdoor unit and BC controller (simultaneous cooling and heating series R2).
• Series R2 is designed to operate in a system that the refrigerant pipe from an
outdoor unit is received by BC controller and branches at the BC controller to
connect between indoor units.
• For constraints on pipe length and allowable difference of elevation, refer to
the outdoor unit manual.
• The method of pipe connection is brazing connection.
Cautions On Refrigerant Piping
u Be sure to use non-oxidative brazing for brazing to ensure that no for-
eign matter or moisture enter into the pipe.
u Be sure to apply refrigerating machine oil over the flare connection
seating surface and tighten the connection using a double spanner.
u Provide a metal brace to support the refrigerant pipe so that no load is
imparted to the indoor unit end pipe. This metal brace should be pro-
vided 50 cm away from the indoor unit's flare connection.
8
Insulating material's thickness
More than 10 mm [7/16 in]
More than 15 mm [5/8 in]
R410A
Gas pipe
Pipe size
O.D. ø12.7 mm (1/2")
O.D. ø15.88 mm (5/8")
B Refrigerant piping (liquid)
D Control box
F Air outlet
6.3. Request for refrigerant piping connec-
tion
Connecting refrigerant piping
• After connecting refrigerant piping, insulate the joints (flared joints) with ther-
mal insulation tubing as shown below.
[Fig. 6.3.1] (P.3)
A Thermal insulation tubing 1
B Caution:
Pull out the thermal insulation on the refrigerant piping at the site, braze the piping,
and replace the insulation in its original position.
Take care to ensure that condensation does not form on exposed copper piping.
C Refrigerant piping (liquid)
E Main body
G Site refrigerant piping
H Ensure that there are no gaps between the insulation and the main body.
I Thermal insulation tubing (small) (accessory) 1
J Tie band (large) (accessory) 4
K Ensure that there is no gap here. Place join upwards.
L Thermal insulation tubing (large) (accessory) 2
M Cut
N Release gas before removing the brazing.
O Thermal insulation
Q Pipe end
S Return to original position
Caution:
Before removing the brazing, cut off the end of the pipe to release any gas.
If the gas is not released, the pipe may fly off.
1. Pull out the thermal insulation on the site refrigerant piping, braze the unit
piping, and replace the insulation in its original position.
* Before brazing the refrigerant piping, always wrap the piping on the main
body, and the thermal insulation piping, with damp cloths to prevent
heat shrinkage and burning the thermal insulation tubing. Take care to
ensure that the flame does not come into contact with the main body itself.
Refrigerant amount adjustment
Refer to the installation manual for the outdoor unit for details on adjusting the
amount of refrigerant.
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
malfunction 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 seam-
less 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, shaving 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.
• Use ester oil, ether oil or alkylbenzene (small amount) as the refrigera-
tor 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.
D Refrigerant piping (gas)
F Thermal insulation tubing 2
P Pull
R Wrap with damp cloth
T Ensure that there is no gap here.