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5 Piping installation
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If the temperature is higher than 30°C and the humidity is higher
than RH 80%, the thickness of the insulation materials should be at
least 20 mm to prevent condensation on the surface of the
insulation.
5.2
Connecting the refrigerant piping
DANGER: RISK OF BURNING/SCALDING
WARNING
▪ Only use R32 as refrigerant. Other substances may
cause explosions and accidents.
▪ R32 contains fluorinated greenhouse gases. Its global
warming potential (GWP) value is 675. Do NOT vent
these gases into the atmosphere.
▪ When charging refrigerant, ALWAYS use protective
gloves and safety glasses.
5.2.1
About connecting the refrigerant piping
Before connecting the refrigerant piping
Make sure the outdoor and indoor unit are mounted.
Typical workflow
Connecting the refrigerant piping involves:
▪ Connecting the refrigerant piping to the indoor unit
▪ Connecting the refrigerant piping to the outdoor unit
▪ Insulating the refrigerant piping
▪ Keeping in mind the guidelines for:
▪ Pipe bending
▪ Flaring pipe ends
▪ Using the stop valves
5.2.2
Precautions when connecting the
refrigerant piping
DANGER: RISK OF BURNING/SCALDING
CAUTION
▪ Use the flare nut fixed to the main unit.
▪ To prevent gas leakage, apply refrigeration oil only to
the inside of the flare. Use refrigeration oil for R32.
▪ Do NOT reuse joints.
WARNING
Connect the refrigerant piping securely before running the
compressor. If the refrigerant piping is NOT connected and
the stop valve is open when the compressor is run, air will
be sucked in. This will cause abnormal pressure in the
refrigeration cycle, which may result in equipment damage
and even injury.
5.2.3
To connect the refrigerant piping to the
outdoor unit
▪ Piping length. Keep field piping as short as possible.
▪ Piping protection. Protect the field piping against physical
damage.
Installation manual
8
1 Connect the liquid refrigerant connection from the indoor unit to
the liquid stop valve of the outdoor unit.
a
c
b
a
Liquid stop valve
b
Gas stop valve
c
Service port
2 Connect the gas refrigerant connection from the indoor unit to
the gas stop valve of the outdoor unit.
NOTICE
It is recommended that the refrigerant piping between
indoor and outdoor unit is installed in a ducting or the
refrigerant piping is wrapped with finishing tape.
5.3
Checking the refrigerant piping
5.3.1
To check for leaks
NOTICE
Do NOT exceed the unit's maximum working pressure (see
"PS High" on the unit name plate).
NOTICE
ALWAYS use a recommended bubble test solution from
your wholesaler.
NEVER use soap water:
▪ Soap water may cause cracking of components, such
as flare nuts or stop valve caps.
▪ Soap water may contain salt, which absorbs moisture
that will freeze when the piping gets cold.
▪ Soap water contains ammonia which may lead to
corrosion of flared joints (between the brass flare nut
and the copper flare).
1 Charge the system with nitrogen gas up to a gauge pressure of
at least 200 kPa (2 bar). It is recommended to pressurize to
3000 kPa (30 bar) in order to detect small leaks.
2 Check for leaks by applying the bubble test solution to all
connections.
3 Discharge all nitrogen gas.
5.3.2
To perform vacuum drying
1 Vacuum the system until the pressure on the manifold indicates
−0.1 MPa (−1 bar).
2 Leave as is for 4-5 minutes and check the pressure:
If the pressure...
Does not change
Increases
3 Vacuum the system for at least 2 hours to a manifold pressure
of −0.1 MPa (−1 bar).
4 After turning the pump OFF, check the pressure for at least
1 hour.
5 If you do NOT reach the target vacuum or CANNOT maintain
the vacuum for 1 hour, do the following:
Then...
There is no moisture in the
system. This procedure is
finished.
There is moisture in the
system. Go to the next step.
ARXF20~42C5V1B
Daikin room air conditioners
3P519299-12X – 2020.12
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