5 Preparation
Installer and user reference guide
19
RWEYQ8~1 RWEYQ8~14T9Y1B
VRV IV water-cooled system air conditioner
4P452191-1 – 2017.04
≥200 mm
If
Then
≤2 m
≤2 m
b
a
>2 m
≤2 m
≤2 m
≥200 mm
≥200 mm
>2 m
>2 m
b
a
a
To indoor unit
b
Piping between outdoor units
NOTICE
There are restrictions on the refrigerant pipe connection
order between outdoor units during installation in case of a
multiple outdoor unit system. Install according to following
restrictions. The capacities of outdoor units A, B and C
must fulfill the following restriction conditions: A≥B≥C.
a
c
b
A
B
C
a
To indoor units
b
Outdoor unit multi connecting piping kit (first branch)
c
Outdoor unit multi connecting piping kit (second branch)
5.4
Preparing water piping
5.4.1
Water quality requirements
Cooling water
(b)
and
circulation system
Hot water system
(c)
Tendency
(d)
Item
(a)
Circulation
water
Make-up
water
Circulation
water
Make-up
water
Corrosion
Scale
Standard items
pH (25°C)
6.5~8.2
6.0~8.0
7.0~8.0
○
○
Electrical conductivity (mS/m) (25°C)
<80
<30
<30
○
○
Chloride ions (mg Cl
–
/l)
<200
<50
<50
○
Sulfate ions (mg SO
4
2–
/l)
<200
<50
<50
○
Acid consumption (pH 4.8) (mg CaCO
3
/l)
<100
<50
<50
○
Total hardness (mg CaCO
3
/l)
<200
<70
<70
○
Calcium hardness (mg CaCO
3
/l)
<50
<50
○
Ionic-state silica (mg SiO
2
/l)
<50
<30
<30
○
Reference items
Iron (mg Fe/l)
<1.0
<0.3
<1.0
<0.3
○
○
Copper (mg Cu/l)
<0.3
<0.1
<1.0
<0.1
○
Sulfate ion (mg S
2–
/l)
—
○
Ammonium ion (mg NH
4
+
/l)
<1.0
<0.1
<0.3
<0.1
○
Residual chlorine (mg Cl/l)
<0.3
<0.25
<0.3
○
Free carbon dioxide (mg CO
2
/l)
<4.0
<0.4
<4.0
○
Stability index
6.0~7.0
—
—
○
○
(a)
These items represent typical causes of corrosion and scale.
(b)
In a condenser water circuit that uses a closed cooling tower, the closed circuit circulating water and make-up water MUST meet the water quality
standards for the hot water system, and passing water and make-up water MUST satisfy those for the circulation type cooling water system.
(c)
Corrosion has a tendency to occur when water temperature is high (40°C or higher), and if metals with no protective coating are directly exposed
to water, it would be a good idea to take effective measures against corrosion such as adding a corrosion inhibitor or deaeration treatment.
(d)
The circle marks in the columns indicate a tendency for corrosion or scale to develop.
NOTICE
▪ The supply water MUST be clean tap water, industrial
water or clean underground water. Do NOT use purified
or softened water.
▪ Do NOT use once-through water. It may cause
corrosion.
5.4.2
Water circuit requirements
INFORMATION
Also read the precautions and requirements in the
"General safety precautions" chapter.
NOTICE
In case of plastic pipes, make sure they are fully oxygen
diffusion tight according to DIN 4726. The diffusion of
oxygen into the piping can lead to excessive corrosion.
▪
Connecting piping – Legislation.
Make all piping connections in
accordance with the applicable legislation and the instructions in
the "Installation" chapter, respecting the water inlet and outlet.
▪
Connecting piping – Force.
Do NOT use excessive force when
connecting the piping. Deformation of the piping can cause
malfunctioning of the unit.
