Warning

This part has changed significantly since version 3.90; in particular, it has been added a possibility to set different priorities between summer and winter, and priorities for off-peak operation.

The system allows a priority to be assigned to each source, in the form of a number between 0 and 10 (except Opentherm which has priority from 0, that is always available, to 5), via the Source Priority parameter, which determines the priority of the source when the system is in Winter mode.

Since version 3.90, there is also the parameter of the source priority in summer, which allows you to specify the priority of the source when the system is in summer mode; if the parameter is set to 0, the priority in summer will be the same as in winter (default setting).

Lower numbers correspond to higher priorities; the number assigned can be considered as the order of activation: source with priority 1 is the first to be activated, source with priority 2 is the second and so on.

When a source is enabled (that is, all the condition seen before are verified: block signals, enable signals, season, outdoor temperature, etc... ​

) all sources with lower priority are automatically disabled.

Several sources can have the same priority, and in this case, they will be enables at the same time.

Sources with priority 0 (ALWAYS AVAILABLE) have a special management as they are never blocked by other sources, neither they block other sources.

Priorities from 6 to 10 have a special meaning: they allow a source to be activated, if necessary, even when it is outside its optimal outdoor working temperature range.

In particular, priority 1/6 should be read as: Priority 1, if the outdoor temperature is within the configured range for the source, Priority 6, if the outdoor temperature is outside the configured range for the source.

Example

To better explain the use of priorities 6 to 10, consider this very common case: a system is equipped with a heat pump and a boiler. The heat pump is used (in winter) for outdoor temperatures > 5°C, the boiler is used for outdoor temperatures <= 5°C. Both the boiler and the heat pump are equipped with a block signal; if one of them goes into block, you want the other one to switch on regardless of the outdoor temperature.

To achieve the desired behavior, we will configure:

The heat pump, with priority 1/6 and outdoor temperature range from +5°C to +50°C, the boiler with priority 2/7 and outdoor temperature range from -50°C to +50°C;

By doing so, we obtain that:

If everything works correctly and the outdoor temperature is above 5°C, the heat pump will be activated (we are in the optimal range, the priority should be seen as “1”); the heat pump activated at priority 1 blocks the boiler automatically (it has priority 2). If everything works correctly and the outdoor temperature is below 5°C, the boiler is activated (we are outside the optimal range of the heat pump, so it will be seen with priority 6; under these conditions, the boiler has priority 2 and is therefore activated, blocking the heat pump).

If the heat pump is blocked, the boiler is activated (regardless of the outdoor temperature). If the outdoor temperature is below 5°C, but the boiler goes into block, the heat pump is reactivated, as it is seen with priority 6, which is still the highest (numerically the lowest) of the available sources.

to summarize, we can say that if 1/6, 2/7, etc. is selected, it means that the FIRST priority (on the left of the slash) is applied when the outdoor temperature is WITHIN the source enable range, the SECOND priority (on the right of the slash) is applied when the outdoor temperature is OUTSIDE the source enable range.

If ROT A/B/C are selected, they correspond in rotation to priorities 2/3/4, as shown in the table: