The display only shows the currently selected fan speed (factory setting). If bypass and EXT/INT air circulation are enabled, the corresponding symbols indicate the type of air flow.

Air flow selection

When P25 = 1, the following can be selected by users.

  • : External circulation without bypass ( i.e. fresh air via heat recovery unit)
  • : External circulation with bypass ( i.e. fresh air will bypass heat recovery unit)

When P24 = 1, there is an additional selection available.

  • : Internal circulation (i.e. no fresh air from outside)

FAU ECO mode (P02 = 2, P25 = 1)

FAU ECO mode can be enabled via setting P02 = 2 (i.e. FAU ECO can be selected) and P25 = 1 (i.e. external and internal circulations must be enabled).

When FAU ECO mode is selected, the fresh air fan controller automatically switches between internal and external circulations for the air flow as per the ratio defined by P26. E.g., when P26 = 1:5, the controller switches to external circulation for 10 minutes, then internal circulation for 50 minutes. The mode setting repeats automatically within one hour. Other ratios can be selected via P26.

For FAU ECO mode, users can select external circulation without bypass (P24 = 0: disable) and with bypass (P24 = 1: enable).

Fan type and fan speed adjustment

3-speed fan type (P54 = 3) is the factory setting. When P54 is set to:

  • 1, the fan type is 1-speed fan.
  • 2, the fan type is 2-speed fan.
  • 4, the fan type is ECM fan.

Only 1 manual fan speed can be selected for 1-speed fan.

Only 2 manual fan speeds can be selected for 2-speed fan.

Only 3 manual fan speeds can be selected (low, medium and high) for 3-speed fan and ECM fan.


Keylock can be activated or deactivated via parameter P14 (see Control parameters) when the controller is in ON and OFF mode.