HOW DO ZONES AFFECT DEHUMIDIFIERS?

Owned by Marco Serpelloni
Last updated: Jul 19, 2023
3 min read

Each zone can be associated with a Dehumidifier, either for dehumidification or integration function, from the Configuration Zone/1 sub page:

If the zone is linked to a Temperature and Humidity Sensor (see ANALOG AND DIGITAL INPUT MULTIPLEXER) and if the zone is in Comfort or Economy mode (so in the Status column of the Zone Page is Comfort or Economy), the system compares the humidity measured in the zone with the humidity set point set via the Set Relative Humidity parameter in the Zones Parameters sub page: if the measured humidity is higher than the set point, the dehumidifier corresponding to the zone is activated.

Note

Zone temperature control logic is independent from the humidity control logic: a zone can be fulfilled in temperature, but not in humidity. In this case, the main output of the zone will be off, but the associated dehumidifier will be on. The opposite is also true.

The configuration of the dehumidifier determines if it is to operate in summer, winter, or both seasons; therefore, it can be that a zone is outside the set humidity condition, but still the dehumidifier will not be activated because we are in a season in which it is not supposed to operate (typically in winter); for more information, see DEHUMIDIFICATION AND INTEGRATION FUNCTION.

A dehumidifier can be associated with several zones: in this case the dehumidifier is activated if even only one of the associated zones requires its intervention.

Warning

Each zone has its own humidity set, so it is not necessary that the zone that starts the dehumidifier is the one with the highest humidity; if, for example:

  • Zone 1, associated with Dehumidifier 1, has a humidity set at 50% and detects a humidity of 52%

  • Zone 2, associated with Dehumidifier 1, has a humidity set at 60% and detects a humidity of 58%

Dehumidifier 1 will be activated at the request of Zone 1, even though it detects a lower humidity than that of zone 2.

Hysteresis in the on/off logic of dehumidifiers

The algorithm of dehumidifier’s ignition is equipped with hysteresis to prevent rapid on/off of the dehumidifier when the set humidity is close to the set threshold.

In detail:

  • The dehumidifier is activated when the relative humidity is greater than or equal to the Zone Relative Humidity Set

  • The dehumidifier is deactivated when the relative humidity is lower than the Zone Humidity Set – the value of the global parameter Zone Humidity Hysteresis.

If, for example, the humidity set is 55.0% and the Hysteresis global parameter of the humidity zone is 3%:

  • The dehumidifier turns on if the humidity is greater than or equal to 55.0%

  • The dehumidifier turns off is the humidity is lower than 52.0% (therefore when it reaches 51.9%).

For more information, see ZONE SET POINT AND SENSOR SETTING.

Example of Dehumidifier activation

The following is an illustrative example of dehumidifier operation and associated output activation.

Zones associated with dehumidifiers WHITOUT a humidity sensor

A zone equipped with a temperature-only sensor (that is without humidity measurement) can be associated with a dehumidifier; in this case, the zone does not control the dehumidifier (i.e., it never controls its ignition), but it uses the dehumidifier as a “vehicle” to assess the possible formation of condensation; for more details, see DEW POINT MANAGEMENT.