Technical data

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Vitorond 200, VD2A Technical Data
Boiler Control
Multi-Boiler System: Vitorond 200, VD2A with Therm-Control
Function description
The Therm-Control will regulate the motorized butterfly
valves or the heating circuit control unit(s), if the factory-
set temperatures are not reached at the Therm-Control
temperature sensor. In the starting phase (e.g. during
commissioning or after a night or weekend shutdown),
the boiler water flow must be proportionally reduced.
Reduce the flow rate via the heating mixing valve using
the Vitotronic-S MW1/Vitotronic 300-K, MW1B or when
regulating the heating circuits via a Vitotronic 200-
H connected to the boiler control unit. No additional
protection measures are required on-site.
No minimum return temperature needs to be maintained.
No shunt pumps and/or boiler circuit pumps/costly mixing
valves are required for raising the return temperature.
DHW heating
DHW is heated up when the actual temperature falls
below the DHW temperature selected for the tank
temperature sensor, subject to tank heating being enabled
by the time switch. The boiler water temperature is raised
to the set DHW temperature +20 K (36º F) and the tank
primary pump is started, if the boiler water temperature
is 7 K (12.6º F) above the actual tank temperature.
The heating circuit pumps M2 and M3 are switched OFF
and the mixing valves M2 and M3 are closed, subject
to absolute priority being enabled, if the heating circuits
are regulated via the Vitotronic.
Heating operation
Depending on the control unit used, the flow temperature
of heating circuits can be operated in modulating mode,
subject to the outside temperature. The boiler water
temperature is regulated 8K (14.4º F) higher than the
set-point.
Applications
Heating system with manifold installed close to the
boiler. The boiler water flow rate will be reduced via the
motorized butterfly valve.
Main components
Multi-boiler system with:
H Vitorond 200, VD2A, 125 to 270.
H Vitotronic 200-H and
- Vitotronic 100, GC1/GC1B, for every boiler in a
multi-boiler system
and
Vitocontrol-S MW1/Vitotronic 300-K, MW1B, one
required for multi-boiler systems
or
- Vitotronic 100, GC1/GC1B, for every boiler in a
multi-boiler system and
Vitocontrol control panel and integral weather-
compensated control unit Vitocontrol-S MW1/
Vitotronic 300-K, MW1B
- external, weather-compensated cascade control unit
with tank thermostat
H Therm-Control for operating boilers without return
temperature elevating package.