Boiler will not start, display is blank, no lights or response

Safety first: Before opening any electrical compartments, turn off the breaker feeding the boiler.

• Check breaker: Locate the boiler's circuit breaker in the electrical panel. If tripped, reset once. If it trips again immediately, do not continue resetting—call a professional.
• Verify service switch: Many Lochinvar boilers have a nearby service switch. Ensure it is in the ON position.
• Inspect power wiring: With power off, remove the boiler's electrical junction box cover. Check for loose wire nuts, burnt insulation, or disconnected wires. Tighten as needed.
• Check internal fuse: Some Lochinvar controls have a low-voltage fuse on the board. Inspect and replace with the same type and rating if blown.
• Restore power: Turn the breaker back on and test the boiler. If the display remains dead, internal components may have failed.

Professional help: If there is still no power indication after these checks, a technician should test the transformer and control board.