DEGRADED SOURCE

Owned by Marco Serpelloni
Last updated: Oct 02, 2023
3 min read

It is possible to monitor the temperature of a source and determine if it is unable to supply the required energy; when this occurs, the source is considered degraded; when a source is in this state, it is possible to choose whether to leave it on or switch it off, but the source (or sources) that come after it in order of priority are also activated (see SOURCES PRIORITY).

This makes it possible to support a source that fail to satisfy the system.

For degraded source monitoring function, it is necessary that

  • The source is equipped with a probe, set to “to control activation”

  • The source set point settings are correct

To determine whether a source is degraded, the system relies on both temperature and time:

A source is considered “degraded” when for the time set by the Degradation Time, the measured temperature is lower (in heating)/higher (in cooling) than the desired set point by the Delta parameter.

The drop-down menu next to the Degradation Time (expressed in seconds):

  • INCL WIN/INCL SUM = inclusive in winter and in summer (the degraded source is not removed from the request)

  • EXCL WIN/INCL SUM = exclusive in winter and inclusive in summer (the request is removed from the degraded source in winter and kept in summer)

  • EXCL WIN/EXCL SUM = exclusive in winter and in summer (the request is removed from the degraded source)

  • INCL WIN/EXCL SUM = inclusive in winter and exclusive in summer (the request is kept in winter and removed in summer from the degraded source)

Allows you to choose whether the degraded source can remain switched on or not.

The following diagram illustrates the criteria:

When a source is declared “degraded”, the system:

  • Switches the source off or leaves it on according to what has been selected

  • Enables the source (or sources) following in the priority scale (these must also have their set points set for them to be activated once enabled)

The “degraded” status is removed when the source temperature returns to the required set point plus the hysteresis value.

Warning

If the Degradation Time parameter is set to zero, the degraded source determination function is deactivated.

Once the countdown (Degradation Timer) has started, which can be seen in the “Source Status” section, it cannot be changed. For example, if you put in 600 seconds and got to 400, and realize that this is too much, putting 100 will not change the countdown to 100, but it will continue to decrease from 400 seconds.

If you want to change, you have to switch off the system (or at least the request to the source), change the degradation time and then switch back on.

Note

Opentherm as a source cannot degrade, neither as DHW nor as Heating/Cooling. Only sources 1, 2, and 3 can degrade with each other and with the Opentherm source.