Vaillant ecoTEC plus VU Series Operating Instructions Manual page 14

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We recommend a filling pressure of at
least 1 bar (0.1 MPa). If the filling pres-
sure is lower than 0.8 bar (0.08 MPa),
top up the heating water and, in doing
so, increase the excess pressure in the
heating installation.
5.4.2 Topping up and purging the
heating installation
Caution.
Risk of material damage due
to heating water that is ex-
tremely calciferous or corros-
ive or contaminated by chem-
icals.
Unsuitable tap water damages
the seals and diaphragms,
blocks components in the
product and heating installation
through which the water flows
and causes noise.
▶
Only fill the heating installa-
tion with suitable heating wa-
ter.
The heating installation is a sealed sys-
tem. Sufficient filling and purging is the
basis for a well-functioning system.
Have your competent person explain the
filling and purging process to you. Each
heating installation is individual.
Proceed as follows: Fill up, purge and
check the pressure. If required, top up
again.
For products with an integrated domestic
hot water generation and products with a
shift-load cylinder, an appropriate filling
device is available. Use the filling device
to fill the heating installation and create the
required excess pressure.
For products with a connected domestic
hot water cylinder, a filling device must be
set up by the competent person and its
use explained.
14
Recommendation for the excess pres-
sure: At least 1.0 bar (0.1 MPa), max-
imum 2.5 bar (0.25 MPa) with correct act-
ive pressure compensation, good standard
value 1.5 bar (0.15 MPa).
▶
Check the height to which the heating
installation extends (highest radiator).
▶
For each metre of height, also add
0.1 bar (0.01 MPa) to the minimum
excess pressure.
– Example: Minimum excess pressure
1.0 bar (0.1 MPa) -> Height of the
heating installation 8 m (cellar to roof)
= 0.8 bar (0.08 MPa) -> Target filling
pressure = 1.8 bar (0.18 MPa)
▶
Read the pressure level that appears
on the display or on an external mano-
meter, if available. (→ Section 5.4.1)
Note
If the pressure that you select is
too high and it reaches the limit
level, the expansion relief valve
opens. If there is no longer suf-
ficient pressure compensation
through the diaphragm expan-
sion vessel, this may already be
the case at the maximum pres-
sure of 2.5 bar (0.25 MPa).
If the pressure is too low, under
certain circumstances, this may
lead to fault message F.22 and
the product temporarily shuts
down. Fault message F.22 goes
out and the product automatic-
ally works again once a certain
pressure level is reached again.
Operating instructions 0020308119_02