Filling The Condensate Siphon; A Caution; H Note - Vaillant ecoTEC VU 656/4 Installation And Maintenance Instructions Manual

6 Start-up
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 system thoroughly 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 valve 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.
The 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. Error message F.22 ("water
shortage") 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.
• Turn the tap off.
26
Note!
h
Use the test program P.0 to bleed the heating
system: 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
≥ P
vessel (P
system
• Check all connections for leaks.
h Note!
When the boiler starts operating a maintenance
or error message may occur due to falling
system pressure. The message disappears
automatically when the boiler is refilled.

6.2.3 Filling the condensate siphon

1
Fig. 6.3 Filling the condensate siphon
A siphon cartridge (1) is included with the boiler as an
installation kit.
• Fit the siphon cartridge (1) in accordance with the
accompanying installation manual before filling the
condensate siphon.
Installation and maintenance instructions ecoTEC 0020029173_01
+ 0.2 bar).
ADG