Vaillant ecoTEC plus VU Series Installation And Maintenance Instructions Manual - page 18
6 Start-up
18
Installation and maintenance instructions ecoTEC plus 0020029173_04
If the heating installation is full, the indicator on the pressure
gauge must point to the upper half of the grey area when the
heating installation is cold in order to ensure that it operates
smoothly. This corresponds to a filling pressure 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.
6.6
Preventing low water pressure
To prevent damage to the heating installation that is caused
by low filling pressure, the product is fitted with a water
pressure sensor. If the filling pressure falls below 0.06 MPa
(0.6 bar), the product indicates low pressure by displaying a
flashing pressure value. If the filling pressure falls below 0.03
MPa (0.3 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 on the display until a pressure of
0.11 MPa (1.1 bar) or higher has been reached.
▶
If you notice frequent losses in pressure, determine and
eliminate the cause.
6.7
Filling and purging the heating installation
1
1.
Flush the heating installation thoroughly before filling it.
2.
Undo the cap of the automatic air vent (1) by one to two
rotations and leave it open, as the product purges itself
via the automatic air vent even in continuous mode.
3.
Observe the explanations on the topic of Treating
(→ Page 17) heating water.
4.
Connect the filling and drainage tap in the heating in-
stallation to a heating water supply in accordance with
the relevant standards.
5.
Open the heating water supply.
6.
Open all thermostatic radiator valves.
7.
If necessary, check that both service valves on the
product are open.
8.
Slowly open the filling and drainage tap so that the wa-
ter flows into the heating installation.
9.
Purge the lowest radiator until water flows out of the
purging valve without bubbles.
10. Purge all other radiators until the heating installation is
completely filled with water.
11. Close all purging valves.
12. Monitor the rising filling pressure in the heating installa-
tion.
13. Fill with water until the required filling pressure is
reached.
14. Close the filling and drainage tap and the heating water
supply.
15. Check all connections and the entire system for leaks.
16. To purge the heating installation, select the check pro-
gramme P.0.
◁
The product does not start up, the internal pump
operates intermittently and purges either the heating
circuit or the hot water circuit. The display shows
the filling pressure of the heating installation.
17. To be able to carry out the purging process properly,
the heating installation filling pressure must not fall be-
low the minimum filling pressure.
– Minimum heating installation filling pressure:
0.08 MPa (0.80 bar)
Note
The check programme P.0 runs for
6.5 minutes per circuit.
At the end of the filling procedure, the
filling pressure of the heating installation
should be at least 0.02 MPa (0.2 bar) above
the counter-pressure of the expansion
vessel ("Exp") (P
Installation
≥ P
Exp
+ 0.02 MPa
(0.2 bar)).
18. If there is still too much air in the heating installation at
the end of the check programme P.0, repeat the check
programme.
19. Check all connections for leaks.
6.8
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.
1.
Check whether all thermostatic radiator valves and both
service valves on the product are open.
2.
Connect a hose to the drain valve that is located at the
lowest position in the heating system.
3.
Open the radiator valves and the drain valves so that
the water can drain quickly. Start at the next point in the
system and open the purging valves on the radiators so
that the contaminated water can completely drain.
4.
Close the drain cocks.
5.
Refill the heating system with water.
6.
Check that the expansion relief valve of the heating
system is functioning correctly by turning the handle
on the valve.
7.
Check the pressure in the heating system and top up
with water if necessary.
8.
Close the filling valve and the cold water valve.