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Piping installation
Installer reference guide
41
R32 split series
4P751614-2 – 2023.09
f
Charging hoses
g
Vacuum pump
h
Valve caps
i
Service port
j
Gas stop valve
k
Liquid stop valve
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…
Then…
Does not change
There is no moisture in the system.
This procedure is finished.
Increases
There is moisture in the system. Go
to the next step.
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.
INFORMATION
After opening the stop valve, it is possible that the pressure in the refrigerant piping
does NOT increase. This might be caused by e.g. the closed state of the expansion
valve in the outdoor unit circuit, but does NOT present any problem for correct
operation of the unit.
7.4 Charging refrigerant
7.4.1 About charging refrigerant
The outdoor unit is factory charged with refrigerant, but in some cases the
following might be necessary:
What
When
Charging additional refrigerant
When the total liquid piping length is
more than specified (see later).
Completely recharging refrigerant
Example:
▪
When relocating the system.
▪
After a leak.
Charging additional refrigerant
Before charging additional refrigerant, make sure the outdoor unit's
external
refrigerant piping is checked (leak test, vacuum drying).
