When powering the EBC30/EBC31/EBC35 for the first time - and after every shut off - the control goes through an initiation phase. During the initiation it detects all auxilliary equipment connected to the control. Two individual air volumes can be controlled, where one circuit controls the exhaust air and another controls the intake air. This is beneficial when controlling the draft for a boiler while at the same time controlling the supply of combustion air.
When powering the EBC30/EBC31/EBC35 for the first time, the display shows 'No INT'. This is an indication that the 'intake' control circuit is not used. The message is not an error message. The control simply informs the installer that only one circuit is used and that it is the intake circuit that is NOT used.