Function Of The Boiler; Heating Mode; Hot Water Production With Dhw Cylinder (Vu Unit); Hot Water Production With Vuw Unit - Vaillant ecoTEC plus Operating Instructions Manual

3 Equipment and functional description
3.2

Function of the boiler

Your Vaillant ecoTEC plus boiler is a high-efficiency, gas-
fired wall-hung boiler.
In addition to direct combustion heat, high-efficiency
gas-fired wall-hung boilers also use the heat of
condensation of the steam in the exhaust fumes. This
makes them more efficient than traditional boilers.
Furthermore, with condensing technology the exhaust
gas temperatures are much lower than with
conventional boilers, which reduces the heat lost via the
exhaust fumes. In addition, the lower system
temperatures of a heating system with high-efficiency
technology reduce the losses from conduction of heat
and radiation.
Your Vaillant ecoTEC plus boiler generates heat for
heating and/or hot water production.
VU units can be operated together with a domestic hot
water cylinder, which stores a larger volume of hot
water.
VUW units are fitted with built-in hot water production.
3.2.1

Heating mode

In heating mode the boiler heats the hot water and
pumps it through the radiators or underflooring heating
of your home (heating circuit). The hot water pumped
into the heating circuit exits the boiler at flow
temperature, emits its heat into the rooms and flows
back into the boiler once cooled to return temperature.
The heating water is then heated again.
3.2.2 Hot water production with DHW cylinder
(VU unit)
1
Fig. 3.3 Drawing off hot water
When you open a hot water tap (1) (sink, shower, bath,
etc.), the hot water is taken from the domestic hot water
cylinder.
Cold water than flows into the domestic hot water
cylinder in its place. If the hot water temperature in the
domestic hot water cylinder falls below the value set,
8
then the boiler operates automatically and reheats the
domestic hot water cylinder. As soon as the water in the
domestic hot water cylinder has received the set
temperature, the boiler switches off. The heating pump
in your boiler continues to run for a short time in order
to supply the residual heat to the heating circuit.
3.2.3

Hot water production with VUW unit

When you open a hot water tap (1) (sink, shower, bath,
etc.), the boiler operates automatically and supplies hot
water.
When you close the hot water tap. the boiler
automatically stops producing hot water.
The heating pump in your boiler continues to run for a
short time in order to supply the residual heat to the
heating circuit.
If you have activated comfort mode, the boiler
immediately supplies you with hot water at the
requested temperature without yo having to wait for the
water to heat up. For this, the hot water heat exchanger
is kept at a preselected temperature level.
i
To prevent unnecessary energy loss, set the
temperature selector not higher than the
required temperature.
Operating instructions ecoTEC plus 0020124810_FT1b