Vaillant ECOTEC PLUS VU 80 Installation And Maintenance Instructions Manual page 41

12.1.1 Setting the heating partial load
The heating partial load of the Vaillant ecoTEC plus boiler is
factory set to "auto". This means that the unit independ-
ently determines the optimum heating output depending on
the current heat demand of the system. A setting is nor-
mally no longer required. If you still want to set a fixed
maximum heating partial load, you can set a value under
diagnostics code D.000, which equates to the unit output
in kW.
If the unit is operated in cascade, you must increase the fan
speed of the unit partial load to 1500 rpm (diagnostics code
D.050).
If a domestic hot water cylinder (cylinder type VIH) is
installed, you can adjust the partial load setting for the cyl-
inder charging to the cylinder type.
12.1.2 Adjusting pump overrun and pump
operating mode
The pump overrun time for heating mode is set at the fac-
tory to a value of 5 minutes. You can set the pump overrun
under diagnostics code D.001 within the range of 1 minute
to 60 minutes. You can set a different pump operating
mode under diagnostics code D.018. Here you have the
choice between Eco and Comfort.
Comfort (continuously operating pump)
The internal pump is switched on when the heating flow
temperature is not at "Heating off" (¬ Operating instruc-
tions) and the heating requirement is enabled via an exter-
nal controller.
Eco (intermittently operating pump)
In the factory, the Eco pump operating mode is set. This
pump operating mode is useful for removing residual heat
after cylinder charging when the heat demand is extremely
low and large temperature spreads exist between the cylin-
der charging and heating mode target values. This prevents
living rooms from being under-supplied. If there is a heat
demand, the pump is switched on every 25 minutes for
5 minutes once the overrun time has elapsed.
If a system partition is installed, you must set the pump to
Continuous mode (85%) (set diagnostics code D.014 to 4).
12.1.3 Setting the maximum flow temperature
The maximum flow temperature for the heating mode is set
at the factory to 75 °C. You can set this under diagnostics
code D.071 in the range 40 °C to 85 °C.
ecoTEC plus installation and maintenance instructions 0020134823_01
Adapting the unit to the heating installation
12.1.4 Setting the return flow temperature control
If the boiler is connected to an underfloor heating system,
the temperature control can be changed from flow temper-
ature regulation (default setting) to return flow temperature
control under diagnostics code D.017.
12.1.5 Burner anti-cycling time
Setting the burner anti-cycling time
To prevent frequent switching on and off of the burner and
therefore energy loss, an electronic restart lockout is acti-
vated for a specific period each time the burner is switched
off. You can adjust the burner anti-cycling time to the con-
ditions of the heating installation.
The burner anti-cycling time is only activated for the heat-
ing mode.
Hot water handling during a burner anti-cycling time does
not affect the timer.
You can set the maximum burner anti-cycling time in the
installer level under diagnostics code D.002 within the
range of 2 minutes to 60 minutes (default setting: 20 min-
utes). The effective burner anti-cycling time depends on the
current target flow temperature and the maximum burner
anti-cycling time set.
The effective burner anti-cycling times with respect to the
target flow temperature and the maximum set burner anti-
cycling time can be found in the following table.
i
Resetting the remaining burner anti-cycling time
You have two options to reset the remaining burner anti-
cycling time:
1st option
Menu ¬ Reset burner anti-cycling time
The current burner anti-cycling time appears in the display.
> Confirm the reset of the burner anti-cycling time by
pressing the right-hand selection button
("Select").
2nd option
> Press the fault clearance key (¬ Operating instructions).
The remaining burner anti-cycling time following
a regular shutdown in heating mode can be
called up under diagnostics code D.067.
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