18 | Piping installation
Installer and user reference guide
95
RXMLQ8 + RXYLQ10~14T7Y1B*
VRV IV system air conditioner
4P543427-1A – 2020.10
NOTICE
Before starting charging procedures, check if the 7‑segment display indication of the
outdoor unit A1P PCB is as normal (see "To access mode 1 or 2" [4 116]). If a
malfunction code is present, see "24.1 Solving problems based on error
codes"[4142].
NOTICE
Close the front panel before any refrigerant charge operation is executed. Without
the front panel attached the unit cannot judge correctly whether it is operating
properly or not.
NOTICE
In case of maintenance and the system (outdoor unit+field piping+indoor units) does
not contain any refrigerant any more (e.g., after refrigerant reclaim operation), the
unit has to be charged with its original amount of refrigerant (refer to the nameplate
on the unit) by pre-charging before the automatic charging function can be started.
18.4.2 About charging refrigerant
Once vacuum drying is finished, additional refrigerant charging can start.
To speed up the refrigerant charging process, it is in case of larger systems
recommended to first pre-charge a portion of refrigerant through the liquid line
before proceeding with the manual charging. This step is included in below
procedure (see "To charge refrigerant"[498]). It can be skipped, but charging will
take longer then.
A flow chart is available which gives an overview of the possibilities and actions to
be taken (see "To charge refrigerant: Flow chart"[497]).
18.4.3 To determine the additional refrigerant amount
INFORMATION
For final charge adjustment in the test laboratory, please contact your local dealer.
NOTICE
The refrigerant charge of the system must be less than 100kg. This means that in
case the calculated total refrigerant charge is equal to or more than 95kg you must
divide your multiple outdoor system into smaller independent systems, each
containing less than 95 kg refrigerant charge. For factory charge, refer to the unit
name plate.
Formula:
R=[(X
1
×Ø22.2)×0.37+(X
2
×Ø19.1)×0.26+(X
3
×Ø15.9)×0.18+
(X
4
×Ø12.7)×0.12+(X
5
×Ø9.5)×0.059+(X
6
×Ø6.4)×0.022]+A+B
R Additional refrigerant to be charged [in kg and rounded off to 1 decimal place]
X
1...6
Total length [m] of liquid piping size at Øa
A, B Parameters A and B (see tables below)
▪ Parameter A:
In case of a multi-outdoor-unit system, add the sum of the individual outdoor
unit charge factors.
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