Riello ALU PRO power Series Instructions For The Installer And The Technical Assistance Centre page 31

Mistakes to avoid and precautions.
From what we have seen it is therefore important to avoid two factors possibly leading to the above mentioned processes
i.e. contact between air and water in the installation and regular topping up with fresh water.
To eliminate contact between air and water (and to prevent the latter from becoming oxidized), it is necessary:
- that the expansion system be a closed vessel, correctly sized and with the correct pre-loading pressure (to be regularly
checked);
- that the system is always at a pressure higher than that of the atmosphere at any point (comprising the pump suction
side) and under all running conditions (all the water sealing and water couplings in the installation are designed to
resist pressure towards outside, but not for depression);
- that the installation is not made with gas-permeable materials (e.g. plastic pipes for floor systems without an anti-oxy-
gen barrier).
b
Lastly we would like to remind you that the warranty does not cover breakdowns incurred by the boiler due
to deposits and corrosion.
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INSTALLER