8.1.5   Precautions for the installation of the 
outdoor unit
 
Order of installation of the units
The  outdoor  units  must  be  installed  in  decreasing  order  of 
capacity:
Capacity of unit A ≥ capacity of unit B ≥ capacity of unit C.
Unit  -A-,  with  the  highest  capacity,  must  be  closest  the  indoor 
units.
 
 Refrigerant pipe installation between outdoor 
units
•  For FSXN1E and FSXNH(E)
•  For FSXN1E only
≤10
≥500
The length between the connection kit -K- (on the side of the out-
door unit) and the outside unit, must be L
A
 ≤ L
B
 ≤ L
C
 ≤ L
D
 ≤ 10 m.
Place the connection kit at a lower level with respect to the con-
nection of the refrigerant pipes of the outdoor unit.
If the connection kit is placed above the refrigerant pipe connec-
tion of the outdoor unit, keep a maximum of 300 mm between the 
connection kit and the base of the outdoor unit. In addition, an oil 
recovery unit -A- (minimum 200 mm) should be tted between the 
connection kit and the outdoor unit.
If the length of the refrigerant gas and liquid pipes between out-
door units is greater than two metres, the oil recovery unit should 
be tted on the gas pipe to prevent the build-up of refrigerant oil.
Place  the  refrigerant  pipes  of  the  outdoor  units  horizontally,  or 
slightly tilted towards the side of the indoor units to prevent the 
build-up of refrigerant oil at the lowest point -A-.
If the refrigerant pipes are opposite the outdoor unit, there should 
be a minimum of 500 mm between the outdoor units and the con-
nection kits -B- for maintenance operations.
  NOTE
The 500 mm space is required when replacing the unit compressor.
± 15º
Install the connection kits parallel to the oor (± 15°).
30
PMML0294A rev.2 - 07/2014
Piping work and refrigerant charge
PMML0294A_rev.2_02-2014.indb   30 14/07/2014   12:28:19