Refrigerant Pipe Work - Mitsubishi Electric Fresh Master GUF-50RDH4 Installation Instructions Manual

7. Refrigerant pipe work

Warning:
Never charge any types of refrigerant other than those speci-
fied by Mitsubishi Electric. Failure to follow this warning may
result in violation of law, or blowout, explosion or fire when the
product is used, serviced, or disposed of. The types of refriger-
ant that can be used are specified in the manual supplied with
the product or on the product nameplate. Mitsubishi Electric
shall assume no liability for any damage, breakdown, malfunc-
tion, or accident resulting from the charging of a refrigerant not
specified by Mitsubishi Electric.
7.1. Refrigerant pipe specifications
To avoid dew drops, provide sufficient insulation to the refrigerant
and drain pipes.
When using commercially available refrigerant pipes, be sure to use
commercially available insulation (with a heat-resisting temperature
of more than 120°C and thickness given below) onto both liquid and
gas pipes.
Be also sure to use commercially available insulating material (with
a formed 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
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.
e.g. 30 mm thickness is necessary under 30°C and 80%RH.
3 If there are customer's specifications, simply follow them.
4 Refrigerant pipe specifications
Model
Item
Refrigerant pipe
Liquid pipe
(Flare connection)
Gas pipe
5 Torque specifications
Outerdia of copper pipe
ø6.35
ø9.52
ø12.7
ø15.88
6 Refrigerant system diagram
Heat exchanger
Strainer
Insulating material's thickness
More than 12 mm
More than 15 mm
GUF-50RDH4 GUF-100RDH4
GUF-50RD4 GUF-100RD4
ø6.35 ø9.52
ø12.7 ø15.88
Tightening torque
14 - 18 N . m
34 - 42 N . m
49 - 61 N . m
68 - 82 N . m
Gas pipe thermistor TH3
Liquid pipe thermistor TH2
Strainer
Flare con-
nection
Linear expansion valve
7.2. Refrigerant piping work
This piping work must be done in accordance with the installation
manuals for both outdoor unit and BC controller (simultaneous cool-
ing and heating series R2).
- With R2 systems connect Fresh Masters to BC controllers.
- For constraints on pipe length and allowable difference of eleva-
tion, refer to the outdoor unit manual.
- The method of pipe connection is flare connection.
- After finishing the piping work, check gas leakage.
Cautions On Refrigerant Piping
Be sure to use non-oxidative brazing for brazing to ensure
that no foreign matter or moisture enter into the pipe.
Be sure to apply refrigerating machine oil over the flare con-
nection seating surface and tighten the connection using a
double spanner.
Provide a metal brace to support the refrigerant pipe so that
no load is imparted to the Fresh Master end pipe. This metal
brace should be provided 50 cm away from the Fresh Mas-
ter's flare connection.
Warning:
When installing and moving the unit, do not
charge it with refrigerant other than the refrigerant
(R410A, R407C) 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 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, shaving par-
ticles, 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 refriger-
ant 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
refrigerator oil to coat flares and flange connections. (For us-
ing R407C, R410A)
- The refrigerant used in the unit is highly hygroscopic and mixes
with water and will degrade the refrigerator oil.
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