Ideal furnace shows F12, unit may start but shuts down at random, sometimes with display flicker

Safety: Work on mains wiring only if you are competent and legally allowed. Otherwise, call a qualified electrician or technician.

Steps:

• Check breaker and supply: Ensure the furnace breaker is fully on and not tripping. Avoid sharing the circuit with heavy loads that may cause voltage dips.
• Inspect power connections: With power off, remove the electrical cover and check that all screws on the line, neutral, and earth terminals are tight.
• Look for signs of overheating: Discoloration or melted insulation near the power entry indicates overheating and requires professional repair.
• Monitor behavior: After tightening connections, restore power and observe operation. If F12 recurs, the internal transformer or control board may be failing and should be replaced by a technician.