Boiler will not start at all; display is blank and no lights or sounds are present.

Safety first: Turn off the breaker before removing any covers. Only qualified persons should work on line-voltage wiring.

• Check breaker and switch: Verify the boiler's circuit breaker is ON and the service switch near the Laars boiler is in the ON position.
• Inspect power cord/wiring: Ensure the power cable or conduit to the boiler is intact and connections at the junction box are tight.
• Look for internal fuse: Some Laars controls have an internal fuse. If accessible, visually inspect for a blown fuse, but replacement should be done by a technician.

When to call a professional: If power is present at the boiler but the display remains dead, the control board or internal fuse likely needs professional service.