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Piping installation
Installer reference guide
43
2(A)MXM40+50 + 2(A)MXF40+50
R32 Split series
4P600463-2C – 2020.08
Before checking the refrigerant piping
Make sure the refrigerant piping is connected between the outdoor unit and the
indoor unit.
Typical workflow
Checking the refrigerant piping typically consists of the following stages:
1
Checking for leaks in the refrigerant piping.
2
Performing vacuum drying to remove all moisture, air or nitrogen from the
refrigerant piping.
If there is a possibility of moisture being present in the refrigerant piping (for
example, water may have entered the piping), first carry out the vacuum drying
procedure below until all moisture has been removed.
7.3.2 Precautions when checking the refrigerant piping
INFORMATION
Also read the precautions and requirements in the following chapters:
▪
"2 General safety precautions"
▪
"7.1 Preparing refrigerant piping"
NOTICE
Use a 2-stage vacuum pump with a non-return valve that can evacuate to a gauge
pressure of −100.7 kPa (−1.007 bar)(5 Torr absolute). Make sure the pump oil does
not flow oppositely into the system while the pump is not working.
NOTICE
Use this vacuum pump for R32 exclusively. Using the same pump for other
refrigerants may damage the pump and the unit.
NOTICE
▪
Connect the vacuum pump to the service port of the gas stop valve.
▪
Make sure that the gas stop valve and liquid stop valve are firmly closed before
performing the leak test or vacuum drying.
7.3.3 To check for leaks
NOTICE
Do NOT exceed the unit's maximum working pressure (see "PS High" on the unit
name plate).
NOTICE
Make sure to use a recommended bubble test solution from your wholesaler. Do not
use soap water, which may cause cracking of flare nuts (soap water may contain salt,
which absorbs moisture that will freeze when the piping gets cold), and/or lead to
corrosion of flared joints (soap water may contain ammonia which causes a corrosive
effect 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.