Order No. 2104 ..
4.2.4.4.9 Valve protection
Valve protection may be carried out periodically in order to prevent the addressed control valves
of the heater or cooling system from becoming calcified or stuck. When set to "Yes", the "Valve
protection" parameter in the "Room temperature control -> Controller functionality" parameter
node activates valve protection.
This type of protection is generally started not only for non-active command value objects, i.e.
for objects which have not requested any heating or cooling energy over the past 24 hours. For
these objects, by taking into account the following parameterisation the controller will
periodically set the command value to the maximum value once a day for a duration of
approx. 5 minutes.
Command value output not inverted:
-> 1-bit command value: "1", 1-byte command value: "255"
Command value output inverted:
-> 1-bit command value: "0", 1-byte command value: "0"
Thus even long closed valves will be opened briefly on a regular basis.
i
A controller disable has no influence on the valve protection. This means that valve
protection is carried out, even when the controller is disabled.
i
The controller checks the 24-h time cycle for the valve protection based on a 24-hour
counter. (Owing to inaccuracies, it can be assumed that this time will shift.) After a reset of
the device (programming with the ETS or return of bus voltage), this will be reset
automatically and restarted.
Page 110 of 171
Software "KNX CO2 sensor"
Functional description
