Central Cooling; Smart Grid (Sg) - Viessmann Vitotronic 200 Operating Instructions Manual

Appendix
Terminology
(cont.)
Mixer
Central heating
A mixer mixes the heated heating water with the
cooled water returning from the heating circuit. The
water, thus brought to the right temperature, is pumped
to the heating circuit by the heating circuit pump. The
heat pump control unit adjusts the heating circuit flow
temperature via the mixer to suit different conditions,
e.g. changing outside temperatures.
Room temperature
■ Standard room temperature:
Set the standard room temperature for periods when
you are at home during the day.
■ Reduced room temperature:
For periods when you will be absent or during the
night, set the reduced room temperature; see: "Heat-
ing mode/cooling mode".
Room temperature for ventilation:
■
This room temperature influences activation of the
bypass: see "Controlled mechanical ventilation".

Smart Grid (SG)

To enable you to use Smart Grid, your contractor has
connected the heat pump control unit to the mains
supply via 2 switching contacts. The power supply util-
ity can use these switching contacts to match opera-
tion of the heat pump to the current grid utilisation
level.
The following 4 options for grid utilisation are taken
into account:
1. Not a lot of power in the grid (grid overload):
The power supply utility can block the heat pump if
not a lot of power is available.
The appliance restarts automatically with the selec-
ted operating program as soon as the power supply
utility enables the power supply again.
During power-OFF, central heating is provided by
the heating water buffer cylinder. If no heating water
buffer cylinder is installed or its temperature is too
low, the rooms are heated using the available auxili-
ary heaters, e.g. oil boiler, electric booster heater.
DHW can only be heated during the power-OFF
period using the auxiliary heaters.
2. No excess power, normal grid utilisation:
The heat pump is operated according to its settings
and the agreed conditions (electricity price).
94

Central cooling

The flow temperature is also set via a mixer with cen-
tral cooling.
In addition, the flow temperature is kept above the con-
densation point of the indoor air (dew point) via a
mixer. This prevents condensation forming on the floor.
3. Small amount of excess power:
The power supply utility provides the power at no
cost.
If a time phase is active in the time program, the
heat pump is started. To utilise the cheap power,
you can raise the set temperature for the following
functions or lower it for cooling:
DHW heating
■
Heating the heating water buffer cylinder
■
■ Central heating
■ Central cooling
■ Enable electric booster heater
Note
The functions that can be utilised depend on the
heat pump type.
4. Large amount of excess power:
The power supply utility provides the excess power
at no cost.
The power supply utility starts the heat pump imme-
diately, even if no time phase is active in the time
program. System components are heated to the
max. possible temperatures or cooled to the min.
possible temperatures.
Information about operation with cheap and free
electricity
Electric power consumptions of the heat pump and the
electric booster heater are not taken into account when
calculating the seasonal performance factor.