NOTICE
▪ 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
(Example: FW68DA).
▪ Do NOT reuse joints.
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
DANGER: RISK OF EXPLOSION
Do NOT open the stop valves before the vacuum drying is
finished.
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:
ARXD25+35A5V1B
R32 Split series
3P650253-15Q – 2022.12
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:
▪ Check for leaks again.
▪ Perform vacuum drying again.
NOTICE
Make sure to open the stop valves after installing the
refrigerant piping and performing vacuum drying. Running
the system with the stop valves closed may break the
compressor.
6
Charging refrigerant
6.1
About charging refrigerant
The outdoor unit is factory charged with refrigerant, but in some
cases the following might be necessary:
What
Charging additional refrigerant
Completely recharging refrigerant Example:
Charging additional refrigerant
Before charging additional refrigerant, make sure the outdoor unit's
external refrigerant piping is checked (leak test, vacuum drying).
INFORMATION
Depending on the units and/or the installation conditions, it
might be necessary to connect electrical wiring before you
can charge refrigerant.
Typical workflow – Charging additional refrigerant typically consists
of the following stages:
1 Determining if and how much you have to charge additionally.
2 If necessary, charging additional refrigerant.
3 Filling in the fluorinated greenhouse gases label, and fixing it to
the inside of the outdoor unit.
Completely recharging refrigerant
Before completely recharging refrigerant, make sure the following is
done:
1 All refrigerant is recovered from the system.
2 The outdoor unit's external refrigerant piping is checked (leak
test, vacuum drying).
3 Vacuum drying on the outdoor unit's internal refrigerant piping is
performed.
Typical workflow – Completely recharging refrigerant typically
consists of the following stages:
6 Charging refrigerant
Then...
There is no moisture in the
system. This procedure is
finished.
There is moisture in the
system. Go to the next step.
When
When the total liquid piping
length is more than specified
(see later).
▪ When relocating the system.
▪ After a leak.
Installation manual
9
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