The defrosting functions require a reference of pressure drop value for the clean heat exchanger. This value is obtained during the calibration process.


Calibration settings




Variable

Available options & Selection

Note


Defrosting configuration

Configuration > Functions > Temperature control > Sectional defrosting

Automatic calibration

| Off | Auto |

Calibration settings

Max setpoint deviation extract air fan when auto calibration

[10] %

Manual calibration

| Off | On |

Actual calibration pressure exchanger extract

___ Pa

The latest values of the exchanger's pressure drop / airflow calibration

Calibration flow extract

___ m3/h


Manual calibration is performed during the final inspection in the factory. The manual calibration is switched to "On" when the AHU is running at nominal speed. The value of the pressure drop over the exchanger's extract-exhaust sides and the related airflow values are stored as a reference point.

Manual calibration shall also be performed after maintenance or cleaning of the exchanger.


While in continuous operation, the exchanger collects dirt which increases the initial pressure drop, therefore adjustment of the reference point is needed. Automatic calibration corrects the reference point every 720 running hours during warm season (Outdoor air temperature > +15 oC). Automatic calibration starts when the extract air fan is running within 10% offset of the setpoint speed.