Furnace indicates circulation pump fault, unit overheats or shuts down quickly after firing

Safety first: Isolate power and allow the system to cool. Close isolation valves around the pump if present.

• Check pump operation: With power on and a heat demand, touch the pump body carefully. It should vibrate slightly and feel warm. If silent and cold, it may not be running.
• Manual freeing (if design allows): Turn off power. On some pumps there is a central screw cap. Place a towel under it, unscrew carefully to release any trapped air and water. Use a screwdriver to gently turn the shaft. Refit the cap securely.
• Bleed air: Open any automatic air vents near the pump to release trapped air.
• Electrical check: Ensure the pump’s electrical connector is fully seated and not burnt. If the pump still does not run, it likely needs replacement.

Warning: Pump replacement involves draining part of the system and resealing joints. If you are not comfortable with plumbing and electrical work, call a professional.