7
5. Refrigerant piping work
Fig. 5-2
Fig. 5-1
5.1. Refrigerant pipe (Fig. 5-1)
► Check that the difference between the heights of the indoor and outdoor
units, the length of refrigerant pipe, and the number of bends in the pipe are
within the limits shown below.
Models
(A) Pipe length
(one way)
(B) Height
difference
(C) Number of
bends (one way)
SM71
Max. 30 m
Max. 30 m
Max. of 10
• Height difference limitations are binding regardless of which unit, indoor or out
-
door, is positioned higher.
• Refrigerant adjustment ... If pipe length exceeds 7 m, additional refrigerant (R32)
charge is required.
(The outdoor unit is charged with refrigerant for pipe length up to 7 m.)
Pipe length
Up to 7 m
No additional charge is required.
Maximum
amount of
refrigerant
Exceeding
7 m
Additional charge is required.
(Refer to the table below.)
Refrigerant
to be added
SM71
40 g × (refrigerant piping length (m) -7)
2.37
(1) Table below shows the specifications of pipes commercially available.
Model
Pipe
Outside diameter Min. wall
thickness
Insulation
thickness
Insulation
material
mm
inch
SM71
For liquid
9.52
3/8
0.8 mm
8 mm
Heat resisting
foam plastic
0.045 specific
gravity
For gas
15.88
5/8
1.0 mm
8 mm
(2) Ensure that the 2 refrigerant pipes are well insulated to prevent condensation.
(3) Refrigerant pipe bending radius must be 100 mm or more.
Caution:
Using careful insulation of specified thickness. Excessive thickness prevents
storage behind the indoor unit and smaller thickness causes dew drippage.
• Be sure to have appropriate ventilation in order to prevent ignition. Furthermore,
be sure to carry out fire prevention measures that there are no dangerous or flam
-
mable objects in the surrounding area.
• R32 maintenance refilling: Before servicing refilling the equipment with R32 to
ensure that there is no risk of explosion from electrical sparks it must be ensured
that the equipment machine is 100% disconnected from the mains supply.
A
B
(C)
(B)
(A)
A
B
A
Indoor unit
B
Outdoor unit
A
Indoor unit
B
Outdoor unit
ø9.52
ø15.88
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