Furnace will not start at all, no display or lights on Weishaupt controller

Safety: Do not work inside live electrical panels. If unsure, call an electrician.

Steps:

• Check breaker: Locate the furnace circuit breaker in your electrical panel. Reset if tripped. If it trips again immediately, do not force it—there may be a short circuit.
• Main switch: Ensure the furnace's main power switch near the unit is in the ON position.
• Fuses: Some Weishaupt controls have internal fuses. With power off, a technician can check and replace blown fuses with the correct rating.