Why is the airhandling unit locked to one speed?

If the airhandling unit cannot be adjusted and appears to be running at a single fixed speed, this may seem like a fault. In many cases, this is due to an external function or component overriding normal operation.

If the ventilation unit is locked to one speed, it is usually because something is overriding the control system. This may, for example, be a humidity sensor, a pressure switch, a kitchen hood, or another type of external control that temporarily has priority. To identify the cause and ensure correct operation, it is recommended to contact a service company or the installer of the system.