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Shutdown during economy and holiday mode
This function ensures that the system shuts down after the change from normal to economy or holiday mode,
to safeguard that the reduced room temperature is achieved.
Operating details (multiple-boiler control unit)
The supply temperature setpoint is 32 ºF / 0 ºC based on the set value.
Room setpoint temperature
Room setpoint temperature according to the operating status
In the ” Nominal value” menu, the room temperature can be set for operating states ”Normal, Economy and Hol-
iday mode“.
Assumed room temperature (without room temperature sensor)
The current room temperature is determined (estimated) by the control unit.
This estimate is based on the current outdoor temperature and the cool down characteristics of the building. To
achieve this, a building type (type of construction and thermal insulation) must be entered. You have the option
of ”Light”, ”Medium” and ”Heavy” building types.
Nominal value (multiple-boiler control unit)
Depending on the type of construction, enter the building type as light, medium or
heavy.
Cascade Control heating curve
The primary function of the Viessmann Cascade Control is to control the “cascading” or staging of up to four
Vitodens 200, WB2-44/60 boilers. It does this by communicating with each individual Vitodens boiler control
via the
KM-BUS communication module.
The control uses its own heating curve, as well as dedicated outdoor and supply temperature sensors. Controls
such as the Vitotronic or Trimatik use the slope, shift and warm weather shutdown (WWSD) settings, while the
Cascade Control uses a number of fixed points to achieve the same goal.
Two fixed points on a grid show how the control calculates the relationship of outdoor temperature to supply
temperature. As the points are moved back and forth or up and down on the grid, the supply temperature is
recalculated based on outdoor temperature changes.
The steeper the slope, the higher the supply temperature with respect to a smaller change of outdoor
temperature. By decreasing the slope, changes in the supply temperature are more gradual over a greater range
of outdoor temperature.
The Cascade Control uses four fundamental points to vary the sloped line: Outside Temperature Fixed Point,
Flow Temperature Fixed Point, Outside Temperature Climazone and Flow Temperature Climazone. Along with
these four points, several other settings can modify the operation of the control: curvature setting,
normal/economy/holiday room setting, minimum and maximum flow settings.
The following illustrations show the anatomy of the Cascade Control heating curve.
5285 565 v1.35285 565 v1.3
Flow 30ºC
Desired 0ºC
Building constr
Light
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