Refrigerant Piping Work - Mitsubishi Electric P Series Installation Manual

11. Refrigerant piping work

For constraints on piping length and allowable difference of
elevation, refer to the design section of the engineering manual.
connection.
Provide proper bracing for refrigerant piping so no load is imparted
upon the connections at the air handler.
Warning:
When installing and moving the unit, do not charge it with
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)
B280 Standard for 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 particles, oils,
moisture, or any other contaminant.
Never use existing refrigerant piping.
Caution: COIL UNDER PRESSURE
Always wear safety glasses when working around
pressurized devices.
The air handlers are shipped with a nitrogen holding
charge in the coil. Carefully follow these instructions when
releasing the charge.
gas.
Both refrigerant lines need to be insulated all the way up to
the cabinet. Make sure the openings in the cabinet around the
refrigerant lines are sealed. 3/8 in thick insulation is the minimum
recommended thickness. Based on ambient conditions, local codes
and line length, thicker insulation may be desired.
A inch
(mm)
Pipe
Nut
Clutch
diameter
(mm)
type
inch (mm)
tool for
R410A
1/4 (6.35) (17)
3/8 (9.52) (22)
0 to 0.02
(0 to 0.5)
1/2 (12.7) (26)
5/8 (15.88) (29)
Tightening torque
lb•ft
N•m
(kgf•cm)
10 to 13
13.7 to 17.7
(140 to 180)
25 to 30
34.3 to 41.2
(350 to 420)
36 to 42
49.0 to 56.4
(500 to 575)
54 to 58
73.5 to 78.4
(750 to 800)
-Never use existing refrigerant piping.
-The large amount of chlorine in conventional refrigerant and
refrigerant oil in the existing piping will cause the new refrigerator to
deteriorate.
-Store the piping to be used during the 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
connecting.
-The refrigerant used in the unit is highly hydroscopic and mixes
with water which will degrade the refrigerant oil.
17