Required; A Caution - Vaillant ecoTEC VU 466/4 Installation And Maintenance Instructions Manual

If the heating installation serves several floors, the
values for the water pressure in the system may need
to be higher (to avoid the ingress of air).
• Flush through the heating installation throroughly
before actually filling it.
1
Fig. 6.2 Automatic air vent
• Unfasten the cap on the automatic air vent (1) by one
or two turns (the appliance is bled automatically while
continuously operated via the automatic air vent).
• Open all thermostatic radiator valves in the
installation.
• Connect the system's combined filling and emptying
valve to a cold water draw-off valve in accordance
with the standards.
Note!
h
To avoid damaging the appliance through
operation with insufficient water pressure, the
boiler is equipped with a pressure sensor.
This sensor records a lack of pressure if the
pressure value falls below 0.6 bar and the
detected pressure value flashes in the display.
If the pressure falls below 0.3 bar the boiler
switches off. Fault message F.22 ("water
lack") appears in the display. Fill the system up
with water before you start up the boiler again.
This message also appears if you switch the
boiler on when it is empty and disappears
automatically when it is filled.
a Caution!
Risk of damage from leaking water!
If the pressure drops frequently the reason for
the loss of heating water must be identified and
eliminated.
• Open the combined filling and emptying valve and the
draw-off valve slowly and add water until the required
system pressure is shown on the pressure
gauge/display.
• Close the draw-off valve.
Installation and maintenance instructions ecoTEC 0020029172_03
Note!
h
Use the check program P.0 to bleed the heating
installation: The boiler does not start up. The
internal pump runs intermittently and bleeds
the appliance circuit. The pressure is displayed
digitally. Ensure that the system pressure does
not fall below 0.8 bar when bleeding is in
progress. Otherwise the bleeding will not be
carried out properly. The bleeding program
takes about 6.5 minutes to complete.
• Bleed all the radiators.
• Check the system pressure again.
a Caution!
If too much air is still in the system after the
bleeding program is finished it must be started
again! Once the filling procedure is complete
the system pressure should be at least 0.2 bar
above the back-pressure from the expansion
vessel (P P
system
• Check all connections for leaks.
h Note!
When the boiler starts operating a maintenance
or fault message may occur due to falling
system pressure. The message disappears
automatically when the boiler is refilled.
Start-up 6
+ 0.2 bar).
ADG
25