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• Do not use the existing piping in the following cases. Perform new
piping instead.
• The piping is different in size.
• The strength of the piping is insufficient.
• The compressor of the condensing unit previously used caused a
malfunction.
An adverse influence of residual substances, such as the oxidation
of refrigerant oil and the generation of scale, is considered.
• If the indoor unit or outdoor unit is disconnected from the piping for
a long time.
The intrusion of water and dust into the piping is considered.
• The copper pipe is corroded.
• The refrigerant of the condensing unit previously used was other
than R410A (e.g., R404A / R507 or R407C).
The contamination of the refrigerant with heterogeneity is
considered.
• If there are welded connections midway on the local piping, make
gas leakage checks on the welded connections.
6-1 Selection of piping material
• Make sure that the inner side and outer side of the piping used is clean and free of contaminants, such as sulphur, oxide, dust, chips, oil and fat, and water.
It is desirable that the maximum oil adhesion in the piping is 30 mg per 10 m.
• Use the following type of refrigerant piping.
Material: Seamless phosphorus deoxidized copper tube (C1220T-O for a maximum outer diameter of 15.9 mm and C1220T-1/2H for a minimum
outer diameter of 19.1 mm)
Refrigerant piping size and wall thickness: Decide the size and thickness from the following table.
(This product uses R410A. The withstand pressure of O type may be insufficient if it is used for piping with a minimum diameter of
19.1 mm. Therefore, be sure to use 1/2 H type with a minimum thickness of 1.0 mm.
If O type is used for piping with a minimum diameter of 19.1 mm, a minimum thickness of 1.2 mm will be required. In that case, be sure
to perform the blazing of each joint.)
• Be sure to perform piping work within the range specified in the
following tables.
Refrigerant piping length
Max. permissible one-way piping length
(equivalent length)
Total length of the gas pipes between the
outdoor units and the outdoor unit
multi-connection piping kit
(g=g1+g2)
Max. branch piping length (actual length)
Max. difference in
unit below outdoor
height between
unit
indoor and outdoor
unit above outdoor
units
unit
Note
A trap is required at 5 m intervals from the outdoor unit.
Make sure the pressure drop is as small as possible.
Refrigerant piping size
Outdoor unit side
Outdoor unit
multi-connection piping
kit (G1, G2, g1, g2)
Main piping (A,a)
Installation manual
7
Te ≥–20°C
a + b + c + d+g2 ≤130 m
(d is d1 or d2 whichever is longer)
Te <–20°C
a + b + c + d+g2 <100 m
(d is d1 or d2 whichever is longer)
g≤10 m
g1≤g2
b + c + d ≤30 m (d is d1 or d2 whichever is longer)
H ≤35 m (Note)
H ≤10 m
Piping size
Liquid pipe
Ø12.7 x 0.8 (O type)
Ø19.1 x 1.0 (1/2 H type or H type)
• Be sure to insulate the connection piping.
The liquid and gas pipe temperatures are as follows:
Liquid pipe arrival minimum temperature: 0°C
Gas pipe arrival minimum temperature: –45°C
In the case of thickness insufficiency, add additional insulation
material or renew the existing insulation material.
• Renew the insulation material if the insulation material is degraded.
Keep the following points in mind for the reuse of existing heat
exchangers
• Units with insufficient design pressure (since this product is an
R410A unit) require a lower-stage design pressure of 2.5 MPa
[25 bars].
• Units for which the path to the heat exchanger has been routed so
that the flow of refrigerant is from bottom to top
• Units with copper tubing or fan corrosion
• Units that may be contaminated with foreign matter such as
rubbish or other dirt
Gas pipe
Ø34.9 x 1.2 (1/2 H type or H type)
Ø41.3 x 1.45 (1/2 H type or H type)
1
2
g1
G1
g2
G2
4
3
A
B
C
D2
F
E
D1
H
a
5
6
e
f
d1
b
c
d2
1 Master unit
2 Slave unit
3 Outdoor unit multi-connection
piping kit
4 Gas piping
5 Showcase
6 Blower coil
(Unit: mm)
LREQ15+20B7Y1R
Air cooled refrigeration condensing unit
4P360438-1B – 2014.01
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