Preventing Low Water Pressure; Filling The Heating Installation; Flushing The Heating Installation For The First Time ("Cold") - Vaillant ecoTEC exclusive 835 Installation And Maintenance Instructions Manual

9.10

Preventing low water pressure

To ensure that the heating installation operates smoothly,
the indicator on the pressure gauge must point to the upper
half of the grey area or to the middle of the bar graph display
in the display (marked by the dashed limit values) when the
heating installation is cold. This corresponds to a filling pres-
sure of between 0.1 MPa and 0.2 MPa (1.0 bar and 2.0 bar).
If the heating installation extends over several storeys,
higher filling pressures may be required to avoid air entering
the heating installation.
If the filling pressure falls below 0.08 MPa (0.8 bar), the
product indicates low pressure by displaying a flashing
pressure value. If the filling pressure falls below 0.05 MPa
(0.5 bar), the product switches off. The display shows F.22.
▶
Top up the heating water to start the product up again.
The pressure value flashes in the display until a pressure of
0.11 MPa (1.1 bar) or higher has been reached.
9.11

Filling the heating installation

1
1. Flush the heating installation through.
2. Select the check programme P.06.
◁
The prioritising diverter valve moves to the mid-
position, the pumps do not run and the product
does not switch to heating mode.
Note
The cap on the automatic air vent (1) has
already been opened at the factory.
3. Observe the information on treating heating water.
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0020193968_05 ecoTEC exclusive Installation and maintenance instructions
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3
A
B
4. Open all radiator valves (thermostatic valves) of the
heating installation.
5. Fit the double non-return valve (1) of the filling line to
the cold-water isolation valve and secure the valve with
the spring clip (2).
6. To fill, first open the isolation valve (3).
7. Open the isolation valve (4) so that the water flows into
the heating system. Fill the heating system.
8. Purge the lowest radiator until water flows out of the
purging valve without bubbles.
9. Purge all other radiators until the entire heating system
has been filled with water.
10. Close all purging valves.
11. Monitor the rising filling pressure in the heating installa-
tion.
12. Fill with water until the required filling pressure is
reached.
13. After filling, close both isolation valves and disconnect
the filling device by removing the double non-return
valve from the cold-water isolation valve.
Note
Both isolation valves must be closed while
the heating system is operating and the
filling line must be removed from the double
non-return valve again.
14. Check all connections and the entire system for leaks.
9.12 Flushing the heating installation for the first
time ("cold")
Note
The complete heating system must be flushed
at least twice: Once with cold water and once
with hot water in accordance with the following
instructions.
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