3 Piping work and refrigerant charge
Compatibility with the piping of current installations where R22 or R407C is used
SMGB0091 rev.2 - 11/2015
55
3
3.6.2 When the existing air conditioner is a product of another manufacturer
Existing pipes made by other manufacturer can also be used if the following conditions are satisfied:
1
For systems with several indoor units, branch pipes shall be changed to the model specified by Hitachi.
2
Pipes shall be cleaned.
3.6.3 Permissible range for existing air-conditioning pipes
Pipe length in the case of “without cleaning process”
Liquid (mm)
Ø6.35
Ø9.52
Ø12.70
Ø15.88
Thickness (mm)
0.8
0.8
0.8
1.0
Gas (mm)
Ø15.88 Ø19.05 Ø12.70 Ø15.88 Ø19.05 Ø22.20 Ø25.40 Ø15.88 Ø19.05 Ø22.20 Ø25.40 Ø28.58 Ø22.20 Ø25.40 Ø28.58
Thickness (mm) 1.0
1.0
0.8
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
Material
soft-annealed
x
x
x
x
x
x
x
Material drawn
x
x
x
x
x
x
x
x
x
x
x
Performance
capacity
(m)
(4-6) HP
5
(2)
5
(2)
40
(1)
50
50
(4)
-
-
30
(3)
30
(3) (4)
-
-
-
-
-
-
8 HP
-
-
-
-
50
(1) (4)
50
(1)
50
-
50
(1) (3) (4)
50
(1) (3)
50
(3)
-
50
(1) (3)
50
(3)
-
10 HP
-
-
-
-
-
-
-
-
-
50
(1)
50
50
50
(1) (3)
50
(3)
50
(3)
(1). Reducing gas pipe size will reduce cooling capacity due to larger pressure loss in gas piping and narrow operation range.
(2). Reducing liquid pipe size will narrow operation range due to the indoor unit relation with expansion valve capacity. In these cases,
set the DSW2-1 to ON position.
(3). Increasing liquid pipe size will require additional refrigerant charge.
(4). When using Ø19.05 gas pipe (soft-annealed), please switch ON DSW2-4# in the RASC Unit PCB.
Standard
!
C A U T I O N
In case that its thickness is less than the R410A piping specifications, set DSW2, pin 4 ON. With this setting the control system adjusts the
pressure in order to avoid damage to the existing pipe for R22.
3.6.4 Selection of the renewal kit model
Hitachi offers a renewal kit as an accessory.
Recommended renewal kit
Renewal kit
RASC unit
External attachment to RASC unit
[Short pipe (local) + Kit + existing piping]
RASC-(4-6)HNPE
TRF-NP160S
RASC-8HNPE
(*)
RASC-10HNPE
(*)
?
N O T E
(*): The availability of the renewal kit for RASC-(8/10)HNPE is to be confirmed.
!
C A U T I O N
In case that its thickness is less than the R410A piping specifications, set DSW2, pin 4 ON. With this setting the control system adjusts the
pressure in order to avoid damage to the existing pipe for R22.