Furnace blower never turns on; burners run briefly then shut off on high limit.

Safety first: Turn off power before accessing blower components.

Step-by-step checks:

• 1. Listen for blower: During a heat call, if burners light but no air comes from vents and the furnace shuts down on limit, suspect blower issues.
• 2. Inspect blower motor wiring: Check for loose or burned wires at the motor and control board.
• 3. Check blower capacitor (if external): Look for a bulged or leaking capacitor can. Do not touch capacitor terminals without discharging; replacement is best left to a technician.
• 4. Try FAN ON mode: Set thermostat fan to ON. If the blower still does not run, the motor or control board is likely faulty.

When to call a professional: Blower motor and capacitor replacement require electrical knowledge and proper sizing. Have a technician install Philco-compatible parts.