Boiler Control Alternatives
18
VITOROND 200, VD2A
Multi-Boiler System: Vitorond 200, VD2A with Therm-Control
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, for every boiler in a
multi-boiler system
and
Vitotronic 300-K, MW1, one required for
multi-boiler systems
or
-Vitotronic 100, GC1, for every boiler in a
multi-boiler system
and
Vitocontrol control panel and integral
weather-compensated control unit
Vitotronic 300-K, MW1S
-external, weather-compensated cascade
control unit with tank thermostat
H
Therm-Control for operating boilers
without return temperature elevating
package.
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 300-K, MW1 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
tempe20 K / 36ºF and the tank
primary pump is started, if the boiler water
temperature is 7 K / 12.6ºF 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
temperatue of heating circuits can be
operated in modulating mode, subject to the
outside temperature. The boiler water
temperature is regulated 8K / 14.4ºF higher
than the set-point.
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