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7.
R
EFRIGERANT PIPE SIZE AND ALLOWABLE
PIPE LENGTH
All field piping must be installed by a licensed refrigeration
technician and must comply with relevant local and
national regulations.
To persons in charge of piping work:
Be sure to open the shut-off valve after piping
installing and vacuming is complete. (Running the
system with the valve closed may break the
compressor.)
It is forbidden to discharge refrigerant into the
atmosphere. Collect the refrigerant in accordance
with the freon collection and destruction law.
Do not use flux when brazing the refrigerant piping.
For brazing, use phosphor copper brazing filler metal
(BCuP) which does not require a flux.
(If a chlorine flux is used, the piping will corrode, and if
the flux contains fluoride, it will cause the coolant oil to
deteriorate, adversely affecting the coolant piping
system.
7.1. Selection of piping material
Foreign materials inside pipes (including oils for fabrication)
must be ≤30 mg/10 m.
Construction material: phosphoric acid deoxidized seamless
copper for refrigerant.
Temper grade: use piping with temper grade in function of the
pipe diameter as listed in table below.
The pipe thickness of the refrigerant piping should comply with
relevant local and national regulations. The minimal pipe
thickness for R-410A piping must be in accordance with the
table below.
Temper grade of piping
Pipe Ø
material
6.4 / 9.5 / 12.7
15.9
19.1
O = Annealed
1/2H = Half hard
Make sure to use the particular branches of piping that have
been selected.
In case the required pipe sizes (inch sizes) are not available, it is
also allowed to use other diameters (mm sizes), taken the
following into account:
select the pipe size nearest to the required size.
use the suitable adapters for the change-over from inch to
mm pipes (field supply).
Installation manual
6
Minimal thickness
t(mm)
O
0.80
O
1
1/2H
1
8.
P
RECAUTIONS ON REFRIGERANT PIPING
Do not allow anything other than the designated refrigerant to
get mixed into the freezing cycle, such as air, etc. If any
refrigerant gas leaks while working on the unit, ventilate the
room thoroughly right away.
Use R-410A only when adding refrigerant
Installation tools:
Make sure to use installation tools (gauge manifold charge hose,
etc.) that are exclusively used for R-410A installations to
withstand the pressure and to prevent foreign materials (e.g.
mineral oils and moisture) from mixing into the system.
Vacuum pump:
Use a 2-stage vacuum pump with a non-return valve
Make sure the pump oil does not flow oppositely into the system
while the pump is not working.
Use a vacuum pump which can evacuate to –100.7 kPa (5 Torr,
–755 mm Hg).
In order to prevent dirt, liquid or dust from entering the piping,
cure the piping with a pinch or taping.
Installation period
More than a month
Less than a month
Regardless of the
Great caution is needed when passing copper tubes through
walls.
For handling of stop valves, refer to "9.3. How to use the shut-off
valve" on page 8.
Only use the flare nuts included with the unit. Using different
flare nuts may cause the refrigerant to leak.
Always use the supplied copper gasket when connecting the
gas pipe supplied with the unit. See "9. Refrigerant piping" on
page 7.
8.1. Cautions for brazing
Be sure to carry out a nitrogen blow when brazing.
Brazing without carrying out nitrogen replacement or releasing
nitrogen into the piping will create large quantities of oxidized
film on the inside of the pipes, adversely affecting valves and
compressors in the refrigerating system and preventing normal
operation.
When brazing while inserting nitrogen into the piping, nitrogen
must be set to 0.02 MPa with a pressure-reducing valve (=just
enough so that it can be felt on the skin).
1
2
6
1
Refrigerant piping
2
Part to be brazed
3
Taping
4
Hands valve
5
Pressure-reducing valve
6
Nitrogen
Protection method
Pinch the pipe
Pinch or tape the
pipe
period
3
4
5
6
U-4~6ML3DPQ
Urban Multi air conditioner
4PW17809-1C
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