User Manual

10.4 H/C changeover
10.4.1 Application and functions
Use the heating/cooling changeover function block to change over the operating
mode (heating or cooling) in 2-pipe systems.
Applicatio
n
The presele
ction heating/cooling is generated on the device or received as a
heating/cooling signal from the bus.
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The following types of changeover are available for H/C operating mode
preselection:
 Changeover with operating mode selector via operation.
 Changeover by date.
 Changeover with analog input (e.g. to change over by outside temperature or by
flow temperature).
 Changeover with digital input (e.g. to change over via manual switch or via
changeover thermostat in the flow).
If several changeover types are active, the operating mode is determined by the
following priority selection:
1. Operation selector
2. H/C changeover input
3. Heating/cooling acc to calendar
The preselected operating mode heating/cooling is provided in the heat and
refrigeration distribution zone to all other controllers within the same zone.
In a hydraulic circuit, the operating mode heating/cooling can be preselected only
via one point. A fault message is generated, if several changeover signals are sent
simultaneously to the bus within the same distribution zone.
We recommend to enable preselected operating mode H/C at the primary
controller or generation where possible.
Re
commendation
10.4.2 Enable function "Heating/cooling changeover"
To activate "Heating/cooling changeover", select "Yes" in operating line "2-pipe
heating/cooling system".
Config
uration
Main menu > Commissioning > Extra configuration > Heating/cooling ch'over >
Operating line
Range Factory setting
2-pipe heating/cooling system No, Yes No
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Siemens Switching and monitoring device RMS705B CE1P3124en
Building Technologies H/C demand, H/C changeover 01.04.2010