Vaillant ecoTEC plus VU 446/5-5 (H-GB) Installation And Maintenance Instructions Manual page 30

8 Adapting the unit to the heating installation
8.2.3 Resetting the remaining burner anti-cycling
time
1st option
Menu → Reset anti-cycl. time
The current burner anti-cycling time appears in the display.
▶
Confirm the burner anti-cycling time reset by pressing
(Select).
2nd option
▶
Press the reset button.
8.2.4 Setting the pump overrun and pump mode
You can set the pump overrun under D.001 (factory setting:
5 min.).
You can use diagnostics code D.018 to set the pump mode
Comfort or Eco.
In the Comfort operating mode, the internal pump is
switched on when the heating flow temperature is not at
Heating off (→ Operating instructions) and the heat demand
is enabled via an external control.
The Eco operating mode (factory setting) is useful for re-
moving residual heat after hot water generation when the
heat demand is extremely low and large target temperature
spreads exist between the hot water generation and heat-
ing mode target values. This prevents living rooms from be-
ing 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.
8.2.5 Setting the heating pump
8.2.5.1 Pump mode setting
The product is equipped with a stage-controlled high-effi-
ciency pump. In the automatic operating mode (D.014 =
0), the pump stage is controlled in such a way that a con-
stantly available pressure is guaranteed. The target values
for the available pressure in mbar can be called up via the
diagnostics codes:
–
D.122 for the heating circuit
–
D.148 for the domestic hot water circuit
If required, you can manually set the pump mode to five
fixed, selectable stages based on the maximum possible out-
put. This switches the speed regulation off.
▶
To change the pump output, change D.014 to the desired
value.
Note
If a low loss header is installed in the heating
installation, we recommend switching off the
speed regulation and setting the pump output
to a fixed value.
30
8.2.5.2 Help when adjusting a heating installation or
when checking the flow rate
You can use diagnostics code D.029 to display the flow rate
in real time (in l/min).
By setting the automatic pump mode (D.014 = 0) and
defining a target value for the available pressure (e.g.
D.122 = 200 mbar), it is possible to adjust the balancing
valves for the various radiators.
▶
To guarantee that the pump operates, set a permanent
heat demand (using the control or the room thermostat).
▶
Insulate each radiator and/or each radiator group, one
after the other.
▶
Adjust the balancing valve for the circuit by displaying the
flow rate via diagnostics code D.029 in order to achieve
the flow rate that is recommended for the properties of
the radiator and/or radiator group.
8.2.5.3 Product pump curve and operating range
Applicability: VU 446/5-5 (H-GB)
B
1 2
1000
800
600
400
200
0 500 1000
1 Flow range without
operating the product
2 Operating range with
limited flow temperature
and power
3 Pump curve at 100%
PWM
Installation and maintenance instructions ecoTEC plus 0020261389_02
3 4
1500 2000 2500
ΔP constant
4
A Installation volume flow
in l/h
B Remaining pump head
in hPa (mbar)
3000
A