Operation Manual

EN • 11
ENFRRU PL DE IT ES NL
Delta Pro S / Delta Pro Pack : 664Y4900 • E
INSTALLATION
RECOMMENDATIONS FOR THE PREVENTION
OF CORROSION AND SCALING
HOW OXYGEN AND CARBONATES CAN AFFECT THE
HEATING SYSTEM
Oxygen and dissolved gasses in the water of the primary circuit
contribute to the oxidation and the corrosion of the system components
that are made of ordinary steel (radiators, ...). The resulting sludge is then
deposited in the boiler exchanger.
The combination of carbonates and carbon dioxide in the water results
in the formation of scale on the hot surfaces of the installation, including
those of the boiler exchanger.
These deposits in the heat exchanger reduce the water flow rate and
thermally insulate the exchange surfaces, which is likely to damage
them.
Sources of oxygen and carbonates in the heating circuit
The primary circuit is a closed circuit; the water it contains is therefore
isolated from the mains water. When maintaining the system or filling
up the circuit, water renewal results in the addition of oxygen and
carbonates in the primary circuit. The larger the water volume in the
system, the larger the addition.
Hydraulic components without an oxygen barrier (PE pipes and
connections) admit oxygen into the system.
PREVENTION PRINCIPLES
1. Clean the existing system before installing a new boiler
- Before the system is filled, it must be cleaned in accordance with
standard EN14868. Chemical cleaning agents can be used.
- If the circuit is in bad condition, or the cleaning operation was not
efficient, or the volume of water in the installation is substantial
(e.g. cascade system), it is recommended to separate the boiler
from the heating circuit using a plate-to-plate exchanger or
equivalent.
2. Limit the fill frequency
- Limit fill operations. In order to check the quantity of water that
has been added into the system, a water meter can be installed
on the filling line of the primary circuit.
- Automatic filling systems are forbidden.
- If your installation requires frequent water refilling, make sure
your system is free of water leaks.
3. Limit the presence of oxygen and sludge in the water
- A deaerator (on the boiler flow line) combined with a dirt
separator (upstream of the boiler) must be installed according to
the manufacturer's instructions.
- ACV recommends using additives that keep the oxygen in
solution in the water, such as Fernox (www.fernox.com) and
Sentinel (www.sentinel-solutions.net) products.
- The additives must be used in accordance with the instructions
issued by the manufacturer of the water treatment product.
4. Limit the carbonate concentration in the water
- The fill water must be softened if its hardness is higher than 20° fH
(11, 2 ° dH).
- Check regularly the water hardness and enter the values in the
service log.
- Water hardness table :
Water hardness °fH °dH mmolCa(HCO3)2 / l
Very soft 0 - 7 0 - 3.9 0 - 0.7
Soft 7 - 15 3.9 - 8.4 0.7 - 1.5
Fairly hard 15 - 25 8.4 - 14 1.5 - 2.5
Hard 25 - 42 14 - 23.5 2.5 - 4.2
Very hard > 42 > 23.5 > 4.2
5. Control the heating water parameters
- In addition to the oxygen and the water hardness, other
parameters of the water must be checked.
- Treat the water if the measured values are outside the range.
Acidity 6,5 < pH < 8,5
Conductivity < 400 μS/cm (à 25°C)
Chlorides < 125 mg/l
Iron < 0,5 mg/l
Copper < 0,1 mg/l