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11 Filling system
The central heating installation needs to be lled with potable water according to the requirements in chapter
9.3 'Water quality'. For lling or topping up the heating system the installation must be provided with a lling
loop or a ll and drain valve to connect a garden hose i.e.. Use the lling loop according to the following
procedure:
1 Attach the lling loop pipe to the lling loop assembly;
2 Open the lling loop valves;
3 Slowly ll the central heating system up to 1.2 – 1.5 bar;
(at the bottom left a pressure gauge indicates the water pressure in the central heating system)
4 Close the lling loop valves;
5 Vent the entire heating installation starting at the lowest point;
6 Check the water pressure and top up if necessary to 1.2 – 1.5 bar;
7 Check the lling loop valve is closed;
When powering up the boiler (described in chapter 13) an automatic de-aeration program will run to vent the
boiler. During this program the pressure in the central heating needs to be checked, and when necessary,
topped up again.
It may take some time before all the air has disappeared from a lled installation. Certainly during
the rst week sounds may be audible that indicate air. The automatic air vent in the boiler will let this
air escape, causing the water pressure to drop during this period and water will need to be relled
again.
Always remove the lling loop pipe or garden hose after lling or topping up the heating system and
close the connections with a cap nut.