INSTALLATION | Appliance maintenance
32
www.ochsner.com | BIA-EUROPA Mini IWP-EN12
»
Remove the components of the cowl outer casing
from the heat pump.
13.3 Descaling the DHW tank
Material damage
Only use descaling agents that are approved for
use in DHW tanks.
Depending on the DHW temperature and water hardness,
the following water treatments must be carried out in ac-
cordance with DIN 1988-7:2004-12:
dH [°]
δ<60°C
δ>60°C
0-14
none
A
14-21
A
Softening
>21
Softening
B
δ
DHW temperature in °C
A Periodic descaling required
B Use not recommended (reduction of DHW temperature)
In the case of highly fluctuating water quality and high water
temperatures (δ > 60°C), an annual inspection by OCHS
-
NER customer service is recommended.
Take the following steps into account when descaling the
system:
»
Reduce the pressure of the DHW tank.
»
Disconnect the cold water and DHW connection from
the DHW tank.
»
Connect the flushing valve to the DHW tank.
»
Descale the DHW tank.
»
Reconnect the cold water and DHW connection.
»
Fill the DHW tank.
13.3.1
Effect of water quality
Substances in
water
Concentra-
tion
(mg/l or ppm)
Time limits
for analysis after sam-
pling
Total hardness
(°dH)
4-14
No limit
HCO3-/SO4²-
>1.0
<1.0
+
-
No limit
Electrical conduc-
tivity
<10 µS/cm
10-500 µS/cm
>500 µS/cm
0
+
0
No limit
pH[2]
<7.0
7,0-9,0
>9.0
0
+
0
Within 24 h
Alkalinity (HCO3-)
<70
70-300
>300
0
+
0
Within 24 h
Sulphate [1]
(SO4²-)
<100
<200
>200
+
0
-
No limit
Ammonium (NH4+) <2
2-20
>20
+
0
-
Within 24 h
Chlorides (CI-)
<100
100-200
>200
+
0
-
No limit
Free chlorine (CI2) <1
1-5
>5
+
0
-
Within 5 h
Hydrogen sulphide
(H2S)
<0.05
>0.05
+
-
No limit
Free (aggressive)
Carbon dioxide
(CO2)
<5
5-20
>20
+
0
-
No limit
Nitrate [1] (NO3-)
<100
>100
+
0
No limit
Iron [3] (Fe)
<0.2
>0.2
+
0
No limit
Aluminium (Al)
<0.2
>0.2
+
0
No limit
Manganese [3]
(Mn)
<0.1
>0.1
+
0
No limit
1 Sulphates and nitrates act as inhibitors for pit-
ting corrosion caused by chlorides in pH-neutral
environments.
2 Generally speaking, a low pH value (below 6) increas-
es the risk of corrosion and a high pH value (above
7.5) reduces it.
3 Fe3+ and Mn4+ are powerful oxidising agents and
can increase the risk of localised corrosion in stain-
less steels. SiO2 above 150 ppm increases the risk of
scaling.
Explanation
»
[+] Good resistance under normal conditions.
»
[0] Corrosion may occur, particularly if other factors
are rated 0.
»
[-] We do not recommend use.
