User Manual Thermador HMWB30WS 30-Inch Masterpiece Low-Profile Wall Hood

Stainless steel surfaces - Clean stainless steel areas by using mild soapy water and a soft cloth. Wipe in the direction of the stainless steel grain when washing and drying. Rinse with water and wipe dry to avoid watermarks. Do not use cleaners that are abrasive or contain chlorine since both are corrosive to stainless steel. For added shine, apply a stainless steel conditioner and wipe off the excess with a soft cloth.
Painted surfaces - Wash with hot, soapy water and a soft cloth. Rinse and dry. Do not use powdered cleaners, steel wool pads, oven cleaners, and other abrasive cleaning materials

There are several solutions for this problem:
The power source is not turned on. If so, make sure the circuit breaker and the unit's power is on.
The power line and the cable locking connector are not connected properly. Check the power connection and make sure the unit is connected properly.
The switchboard and control board wirings are disconnected. Make sure the wirings between the switchboard and control board are connected properly.
The switchboard or control board is defective.