Preparing Water Piping; Water Quality Requirements; Water Circuit Requirements - Daikin VRV IV W+ Series Installer And User Reference Manual

18 | Piping installation

18.2 Preparing water piping

18.2.1 Water quality requirements

(a)
Item
Standard items
pH (25°C)
Electrical conductivity (mS/m) (25°C)
–
Chloride ions (mg Cl /l)
2–
Sulfate ions (mg SO /l)
4
Acid consumption (pH 4.8) (mg
CaCO /l)
3
Total hardness (mg CaCO
Calcium hardness (mg CaCO
Ionic-state silica (mg SiO
Reference items
Iron (mg Fe/l)
Copper (mg Cu/l)
2–
Sulfate ion (mg S /l)
Ammonium ion (mg NH
Residual chlorine (mg Cl/l)
Free carbon dioxide (mg CO
Stability index
(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.

18.2.2 Water circuit requirements

Installer and user reference guide
78
Cooling water
circulation system
Circulation
water
6.5~8.2
<80
<200
<200
<100
/l) <200
3
/l)
3
/l) <50
2
<1.0
<0.3
+
/l) <1.0
4
/l)
2
6.0~7.0
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.
INFORMATION
Also read the precautions and requirements in the
precautions" [
(b)
and Hot water system
Make-up Circulation
water water
6.0~8.0
<30
<50
<50
<50
<70
<50
<30
<0.3 <1.0
<0.1 <1.0
—
<0.1 <0.3
<0.3 <0.25
<4.0 <0.4
—
4
8].
(c)
Make-up Corrosion
water
7.0~8.0 ○
<30 ○
<50 ○
<50 ○
<50
<70
<50
<30
<0.3 ○
<0.1 ○
○
<0.1 ○
<0.3 ○
<4.0 ○
— ○
VRV IV water-cooled system air conditioner
(d)
Tendency
Scale
○
○
○
○
○
○
○
○
"2 General safety
RWEYQ8~14T9Y1B
4P452191-1B – 2020.10