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Building Technologies
Basic documentation: Communication via the KNX bus
CE1P3127en
HVAC Products
Appendix
30.08.2007
9.2
Heating / cooling changeover
The
universal RMU7x0B controllers
are programmed with the new "H/C
changeover" function block, which is used for changeover of the specified
"Heating" or "Cooling" mode in
2-pipe systems
.
x
H/C changeover
Q
23
The specified "Heating" or "Cooling" mode can be generated in the controller itself,
or received as a "Heating/cooling changeover signal" over the KNX bus.
The following methods of changeover can be programmed for the specified
"Heating/Cooling" mode:
•
Changeover via digital input, e.g. with manual switch or with a changeover
thermostat in the flow (already an option with RMU7x0).
•
Changeover vie analog input, e.g. based on outside air temperature or flow
temperature.
•
Changeover based on the calendar (date): Configured in the "H/C Changeover"
function block (calendar symbol checkbox selected)
•
Changeover with operating mode selector. Configured in the "H/C Changeover"
function block ("Hand" symbol checkbox selected)
The "Heating/Cooling" mode is not affected by the type of changeover.
If several types of changeover are selected, the required operating mode is
determined in the following order of priority:
1. Operating mode selector
2. H / C changeover input
3. Heating/cooling based on calendar
The required "Heating/Cooling" mode is transmitted by the "changeover controller"
to all other controllers in the heating distribution and refrigeration distribution zones.
In a hydraulic circuit, the "Heating/Cooling" mode can be defined in one location
only. If several H/C changeover signals in the same distribution zone are
distributed over the KNX bus, a fault message is generated.
If possible, the required "Heating/Cooling" changeover command should be
activated in the primary controller or generator.
The "H/C changeover" function is activated by setting the operating line "2-pipe
system heating/cooling" to "Yes".
Main menu > Commissioning > Extra configuration > Heating/cooling changeover
Operating line
Range
Factory setting
2-pipe heating/cooling system
No, Yes
No
Use
Effect of specified mode
Note
Activating the function
Configuration