Pipe Requirement; Brazing Connection (Pipe Connection) - Fujitsu AIRSTAGE ARUX12TLAV2 Installation Manual

4.2. Pipe requirement

Refer to the installation manual of the outdoor unit for description of the length of connect-
ing pipe or for difference of its elevation.
• Use pipe with water-resistant heat insulation.
Install heat insulation around both the gas and liquid pipes. Failure to do so may cause
water leaks. Use heat insulation with heat resistance above 248°F (120°C). (Reverse cycle
model only)
In addition, if the humidity level at the installation location of the refrigerant piping is ex-
pected to exceed 70 %, install heat insulation around the refrigerant piping. If the expected
humidity level is 70 to 80 %, use heat insulation that is 9/16 in (15 mm) or thicker and if the
expected humidity exceeds 80 %, use heat insulation that is 13/16 in (20 mm) or thicker.
If heat insulation is used that is not as thick as specified, condensation may form on the
surface of the insulation.
In addition, use heat insulation with heat conductivity of 0.045 W/(m·K) or less (at 68°F
(20°C)).

4.3. Brazing connection (pipe connection)

4.3.1 Bending pipes
• The pipes are shaped by your hands or pipe bender. Be careful not to collapse them.
• Do not bend the pipes in an angle more than 90°.
• When pipes are repeatedly bend or stretched, the material will harden, making it difficult to
bend or stretch them any more. Do not bend or stretch the pipes more than 3 times.
To prevent breaking of the pipe, avoid sharp bends.
If the pipe is bent repeatedly at the same place, it will break.
4.3.2 Pipe connection
The heat exchanger is shipped pressurized with dry nitrogen.
Do not leave piping open to the atmosphere unnecessarily. Water and water vapor are
detrimental to the refrigerant system. Until the piping is complete, recap the system and
charge with nitrogen at the end of each workday. Clean all piping connections before
soldering joints.
Failure to follow these procedures could result in personal injury or equipment damage.
• The gas and liquid pipes connections must be brazed.
• Be sure to braze them before performing any wiring work or installing the drain pipe.
Outer diameter of pipe [in (mm)]
AR12 AR18 AR24
Liquid pipe 1/4 (6.35)
Gas pipe 1/2 (12.70)
(1) Remove the panels.
* Do not lose the grommets that protects the refrigerant pipes.
Grommets
CAUTION
CAUTION
CAUTION
CAUTION
AR30 AR36 AR48
3/8 (9.52)
5/8 (15.88)
(2) First, pass the grommet (for the liquid pipe) through the connection pipe (liquid).
Protect the periphery of brazing area by wet cloth, etc. and then braze the pipes.
: Protect these areas with wet cloth, etc.
Drain pan
Drain ports
Grommet (for
liquid pipe)
Connection
pipe (liquid)
Connection pipe (gas)
(3) After installing the coil access panels, the grommet for the gas pipe can be attached to
the gas pipe. Insert the grommet for the liquid pipe and the gas pipe into each hole on
the panels.
Grommet (for
liquid pipe)
Grommet (for gas pipe)
Be sure to use wet cloth, etc., to protect the pipe heat insulation and grommets. Because
these parts are extremely flammable, they can cause a fire if they are not properly pro-
AR60
tected.
Be sure to use wet cloth, etc., to protect the thermistors. In case the thermistor may be
damaged by heat of brazing, which lead to failure of normal operation.
Do not expose the unit (panel, drain pan, drain port, etc.) to the flame. The exposure of
these parts to the flame will adversely affect their appearance and functions or cause a
water leakage.
If air or another type of refrigerant enters the refrigeration cycle, the internal pressure in the
refrigeration cycle will become abnormally high and prevent the unit from exerting its full
performance.
Apply nitrogen gas while braz-
ing the pipes. Nitrogen gas
pressure:
2.9 psi (0.02 MPa)
(= pressure felt sufficiently on
the back of your hand)
If a pipe is brazed without applying nitrogen gas, it will create an oxidation film.
This can degrade performance or damage the parts in the unit (such as the compressor or
valves).
Do not use flux to braze pipes. If the flux is the chlorine type, it will cause the pipes to
corrode. Furthermore, if the flux contains fluoride, it will adversely affect the refrigerant pipe
system such as by degrading the refrigerant oil.
For brazing material, use phosphor copper that does not require flux.
Remove the thermistor
on the connecting port
(for gas pipe) during
brazing to protect against
heat.
Drain ports
Drain pan
WARNING
CAUTION
Pressure regulating valve
Cap
Nitrogen gas
Brazing area
Thermistors
En-10