Pipe Connection; Sealing Test; Vacuum Process - Rheem RHMV4821SNACJA Manual De Instalación

When using conventional fl are tools to fl are R410A pipes, the dimension A should be
approximately 0.020 in (0.5 mm) more than indicated in the table (for fl aring with R410A
flare tools) to achieve the specified flaring. Use a thickness gauge to measure the
dimension A.
Width across
flats
flats
5.2.2. Bending pipes
• To prevent breaking of the pipe, avoid sharp bends. Bend the pipe with a radius of
curvature of 3-15/16 in (100 mm) to 5-14/16 in (150 mm).
• If the pipe is bent repeatedly at the same place, it will break.
• If pipes are shaped by hand, be careful not to collapse them.
• Do not bend the pipes at an angle of more than 90°.
• When pipes are repeatedly bent or stretched, the material will harden, making it diffi cult
to bend or stretch them any more.
• Do not bend or stretch the pipes more than three times.

5.2.3. Pipe connection

• Be sure to install the pipe against the port on the indoor unit and the outdoor unit
correctly. If the centering is improper, the fl are nut cannot be tightened smoothly. If
the fl are nut is forced to turn, the threads will be damaged.
• Do not remove the fl are nut from the outdoor unit pipe until immediately before
connecting the connection pipe.
• After installing the piping, make sure that the connection pipes do not touch the
compressor or outer panel. If the pipes touch the compressor or outer panel, they will
vibrate and produce noise.
(1) Service cover removal
• Remove the two mounting screws.
• Remove the service cover by pushing downwards.
Direction of
the service
panel removal
(2) Valve cover removal.
• Remove the one mounting screw.
• Remove the valve cover by sliding upward.
(3) Install the outdoor unit wall cap (supplied with the optional installation set or
procured at the site) to the wall pipe.
(4) Connect the outdoor unit and indoor unit piping.
(5) After matching the center of the fl are surface and tightening the nut hand tight,
tighten the nut to the specifi ed tightening torque with a torque wrench.
2-way or 3-way valves
(liquid)
3-way valve
(gas)
9374995721_IM.indb 7 9374995721_IM.indb 7
Pipe outside
Width across fl ats of
diameter [in (mm)]
Flare nut [in (mm)]
3/8 (9.52)
7/8 (22)
5/8 (15.88)
1-1/8 (29)
CAUTION
CAUTION
Hook
(3 places)
Service cover
Valve cover
Hook (4 places)
Flare nut
Connection pipe
(liquid)
Flare nut
Connection pipe
(gas)
CAUTION
Hold the torque wrench at its grip, keeping it in a right angle with the pipe, in order to
tighten the fl are nut correctly.
Flare nut
Holding
spanner
Flare nut
Torque wrench
To prevent gas leakage, coat the
fl are surface with refrigerator oil.
Flare nut [in (mm)]
3/8 (9.52) dia.
5/8 (15.88) dia.

5.3. Sealing test

WARNING
• Before operating the compressor, install the pipes and securely connect them.
Otherwise, if the pipes are not installed and if the valves are open when the
compressor operates, air could enter the refrigeration cycle. If this happens, the
pressure in the refrigeration cycle will become abnormally high and cause damage or
injury.
• After the installation, make sure there is no refrigerant leakage. If the refrigerant leaks
into the room and becomes exposed to a source of fi re such as a fan heater, stove, or
burner, it produces a toxic gas.
• Do not subject the pipes to strong shocks during the sealing test. It can rupture the
pipes and cause serious injury.
CAUTION
Do not block the walls and the ceiling until the sealing test and the charging of the
refrigerant gas have been completed.
• After connecting the pipes, perform a sealing test.
• Make sure that the 3-way valves are closed before performing a sealing test.
• Pressurize nitrogen gas to 4.15 MPa to perform the sealing test.
• Add nitrogen gas to both the liquid pipes and the gas pipes.
• Check all fl are connections and welds. Then, check that the pressure has not
decreased.
• Compare the pressures after pressurizing and letting it stand for 24 hours, and check
that the pressure has not decreased.
* When the outdoor air temperature changes 41°F (5°C), the test pressure changes
0.05 MPa. If the pressure has dropped, the pipe joints may be leaking.
• If a leak is found, immediately repair it and perform the sealing test again.
• After completing the sealing test, release the nitrogen gas from both valves.
• Release the nitrogen gas slowly.

5.4. Vacuum process

CAUTION
• Perform a refrigerant leakage test (air tightness test) to check for leaks using nitrogen
gas while all valves in the outdoor unit are closed. (Use the test pressure indicated on
the nameplate.)
• Be sure to evacuate the refrigerant system using a vacuum pump.
• The refrigerant pressure may sometimes not rise when a closed valve is opened after
the system is evacuated using a vacuum pump. This is caused by the closure of the
refrigerant system of the outdoor unit by the electronic expansion valve. This will not
affect the operation of the unit.
• If the system is not evacuated suffi ciently, its performance will drop.
• Use a clean gauge manifold and charging hose that were designed specifi cally for
use with R410A. Using the same vacuum equipment for different refrigerants may
damage the vacuum pump or the unit.
• Do not purge the air with refrigerants, but use a vacuum pump to evacuate the
system.
Connection pipe
(liquid)
90°
Connection pipe
Tightening torque [ft·lb (N·m)]
24 to 31 (32 to 42)
46 to 55 (63 to 75)
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